Peel to Core - or the home baker's guide to reducing food waste, one delicious dessert at a time

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I pride myself on throwing away little food and actively trying to minimize how much food I waste. I also like to think that reducing food waste requires little more than a bit of creativity and imagination. In fact, my husband often teases me for reminding him not to throw away specific food items and that I will no doubt figure out how to turn them into something delicious, or cheerfully suggesting “well, we can always freeze it for later”. 

There are several ways to think about reducing food waste. The obvious one is to reduce the actual volume of food thrown away - e.g. by finding ways to use up overripe fruit or vegetables that have started to show their age. Another one is to ensure that any food wasted is in fact waste, i.e. you have extracted everything that is edible and flavourful from ingredients that are still safe to eat before you throw the rest away. And the two of course are not mutually exclusive - just take citrus fruits for example. If you buy them for their juice or the fruit itself, you will end up with plenty of peels that most of us typically just throw away. And yet, if you turn the peel into candied peel for future baking projects in the end there is next to nothing left to be thrown away (similarly, if you zest your citrus fruits before juicing). Since the peel is also where the flavour is concentrated you are also making sure you are extracting all that delicious flavour from your citrus fruits before discarding anything. 

Food waste plays a role not just in savoury food but also when it comes to baking and preparing desserts. Not only can baking/desserts create food waste (e.g. a pile of apple peels from making an apple galette, half a dozen egg whites left from making ice cream etc.) but baking and desserts also present plenty of opportunities to use up food that might otherwise go to waste. And I’m not just talking about using up brown bananas to make banana bread!

Below is a short(-ISH) guide with some ideas for how to use up and make the most of common ingredients that might otherwise go to waste. The list is by no means exhaustive - neither when it comes to what leftovers to use nor how to use them. If there are ingredients missing that you would like some ideas for, let me know in the comments below and I’ll try and come up with something! 

Eggs

When it comes to staple ingredients for baking and desserts (think flour, sugar, butter and eggs), flour and sugar have the benefit of being quite shelf stable, i.e. having long expiration dates. And butter has many applications outside of baking and desserts. 

But the one thing that folks easily struggle with are leftover egg yolks and whites. In fact, a quick google will yield many many listicles for using up either. However, most of these are not particularly user-friendly - you often have to click through to the actual recipe to see how many egg yolks a given recipe will use up and how easily the recipe can be scaled up or down. And an ice cream recipe calling for 6 egg yolks is of little help if you are dealing with just one leftover egg yolk! So below is a short guide for the types of recipes you can make depending on how many egg yolks or whites you have to use up.

Egg yolks

• 1 egg yolk: 1 batch of Sweet Shortcrust pastry (enough for a simple tart crust) or
  to use as egg wash to brush on pastries or enriched breads before baking

• 2 egg yolks: A small portion of pouring custard like Creme Anglaise using 250ml of milk

• 3 egg yolks: Claire Ptak’s Egg Yolk Chocolate Chip Cookies 

• 4 egg yolks or more: Many types of custard in larger quantities (a pouring custard like creme anglaise, a set baked custard like flan etc.), ice cream, curds, buttercream etc.

Egg whites

• 1 egg white: a small batch of Torrone/Nougat, a small batch of Royal Icing for decorating cookies, a small batch of marshmallows, a jar of marshmallow fluff 

• 2 egg whites: Six financiers like these Dorito ones I made for fun a while back

• 3 egg whites: A simple apple tart with lots of nuts 

• 4 egg whites or more: Pavlova, Meringue Roulade such as this Ottolenghi Brown Sugar, Apple and Burnt Honey one.

Fruit

How to minimise food waste and maximize flavour extraction when it comes to fruit depends on the type of fruit you are dealing with:

• Citrus fruits: If your recipe only asks for citrus juice it’s good to decide what you want to do with the peels before juicing - e.g. if you want to use the zest, it will be easier to zest your citrus fruits before juicing! You will most likely already be familiar with adding the zest of citrus fruits to different types of cake or muffin batters, pastry dough or when making things like pie fillings, frostings etc. So instead, here are some ideas you might not have come across before: 

  • Next time you are having grapefruit with your breakfast, save the grapefruit peels and collect them in your freezer - once you have 6 halves, go and make David Leibovitz’ Candied Grapefruit Peel to snack on or fold into brioche or scone dough;

  • For a grown-up take on a Sundae, use a mix of zest from different citrus fruits to top some good quality vanilla ice cream together with some olive oil and sea salt;

  • For a last minute edible gift idea or a little something to have with your afternoon coffee use orange zest to make these Sichuan Pepper and Orange Chocolate Truffles;

  • Mix the zest of 1 orange (or equivalent amount of zest from lemons, limes or grapefruits) with 250g sugar (use your fingers to really rub it in). Spread out on a tray and leave to dry for a few hours. Use to sprinkle on fruit salads, to dust fried things like donuts or churros, to flavour fruit fillings for pies and similar, to make cocktails etc. ;

  • Same as above but instead of drying the sugar, add equal amounts of water, then boil until the sugar is dissolved. This makes a beautifully fragrant simple syrup which you can use not just for cocktails but also to brush on cake layers to moisten them before assembly, to drench stale Brioche or similar to make Bostock (see below) etc.

• Apples, pears, quinces etc.: I used to always discard the peels of fruits like apples, pears, quince etc. when baking but I learned from Alice Waters (via Claire Ptak) that fruit peels and cores are an excellent base for making flavoured sugar syrups to add some sheen to things like pie or galette. That doesn’t mean you now need to keep a ziplock back of apple peels and cores in your freezer which you fill every time you eat an apple. But it is a good trick to remember next time you make say an apple tart. Simply add the peels (and even cores) together with some sugar and equal amount of water to a sauce pan. Bring to a boil until syrupy, strain and discard the peels and cores. Brush the syrup over your tart. An alternative is to use the peels to make jelly - like the Quince jelly Nicola Lamb shared in her newsletter the other day.

• Stone fruit pits (plums, peaches, nectarines, apricots, cherries etc.) The kernels inside the pits of stone fruits are deeply aromatic in a bitter almond kind of way. When stone fruit season is at its peak, keep those pits and set them aside to dry. Once dry, you can carefully crack them open with a nutcracker or a mallet and use the little kernel inside of the pit to add when making jam, infuse creams and custards or ice creams or even make flavoured alcohol (think of it as a homemade bitter almond extract of sorts. But note that the flavour is quite subtle  - so you will need plenty of kernel for say a single batch of panna cotta that serves 4.

• Bananas: Banana Bread is an obvious answer (and to stay on topic - I can highly recommend my Zero Waste Banana Bread recipe which also takes care of any sourdough discard and leftover dairy you might need a home for!). And should you be worried about Banana Bread going to waste, fret not, Banana Bread, whole or sliced, freezes incredibly well. Simply freezing sliced or halved bananas that are past your preferred stage of ripeness for future banana ice cream, banana pastry cream etc. is also a good idea.

Pineapple: As delicious as pineapple is finishing a whole pineapple by yourself can be quite an undertaking. And then there is all that pineapple peel! One of the most delicious things you can make with any surplus pineapple is Ottolenghi’s Pineapple and Herb Sorbet. And the peel? Make some Tepache, aka a Mexican spiced and fermented pineapple drink.

Bread / Pastries / Leftover Dough

Bread

Bread - a food almost as old as humanity itself - and yet we haven’t really figured out how to prevent bread from going stale yet (well, some companies have but I am not sure I want to eat bread that is shelf stable for close to a year!). Thankfully though, humanity has figured out many delicious ways of using up stale bread. What to make with your leftover stale bread depends a bit on how much of it you have to hand and even how stale it is:

• Any sort of slightly stale Brioche, Pain de Mie or similar enriched breads are great for Bostock - i.e. France’s love child between French Toast and an Almond Croissant where you soak stale bread in sugar syrup before topping with frangipane and baking in the oven until the whole thing is warm, gooey and sticky. The frangipane layer on top of Bostock is also the perfect opportunity to us up any half empty bags of nuts or even half empty jars of nut butter! Alternatively, these types of bread also make great bread and butter pudding.

• If it’s Sourdough that you have a surplus of, you also have a number of delicious options, my favourite one being to make Caramelised Sourdough Croutons. I initially came up with this recipe to fold into some ice cream but have to say the caramelised bits of sourdough bread are as addictive as Kettle Corn so are worth making just to have as a snack. Sourdough bread also makes for delicious bread crumbs - but don’t just use them in your cooking! Toasted in some butter and mixed with sugar and some cardamom, they make a great topping like for these Sweet Labneh Dumplings with Sumac Cherries. But you can also bake with them - for example you can swap them in for ground nuts in a Dacquoise (a cake made up of several layers of nut studded meringue disks). 

• Danes not only know how to bake delicious Rye bread, they also know how to use up any stale rye bread. You might already be familiar with Danish rye bread porridge (which is far more delicious than it sounds) but if you are looking for something a little bit more special, Marie Frank recently alerted me to the fact that Danes also know how to turn stale rye bread into a delicious layer cake called brødtorte. 

Stale pastries

Having stale pastries around and not know what to do with them might be a luxury problem but one that is easily fixable. You can of course try and soften them by brushing each pastry with a little bit of water before warming them up in a hot oven for 5 minutes. But an even better idea is to turn stale croissants, pains au chocolat etc into Almond croissants or bread and butter pudding. 

Leftover puff pastry, cookie dough, phyllo dough etc. 

Whether I am using store bought or homemade dough, I almost inevitably end up with awkward amounts of leftover dough - too much to throw away, too little to freeze for a later stage. Here are some ideas I have collected over the years:

• Leftover puff pastry can easily be turned into Palmiers - little ear shaped cookies that keep well if stored in an airtight container and are the perfect thing to dunk into your coffee or tea. Plus, you can flavour them whichever way you want - Pictured here are some Garam Masala Palmiers which would be perfect paired with a rich and dark hot chocolate. 

• If you have leftover cookie dough simply bake off the remaining dough as is - once baked and cooled down you can use these cookie offcuts to fold into ice cream or turn into individual serving ice box cakes or pulverize them to use for press-in Pie or Cheesecake Crusts for example. 

• Leftover phyllo dough in sufficient quantities forms the base for one of the most magnificent cakes there is: Greek Portokalopita. An orange and yoghurt cake that is flourless but for the inclusion of dried shards of phyllo dough and that once baked gets drenched in an orange scented sugar syrup. 

Other ingredients

Below is a random selection of a few other leftovers you might find yourself with that don’t fit into any of the categories above. If I think of any other ingredients (or if you have any requests) I will add them to this list with some ideas for how to make the most of them / try and prevent them going to waste: 

• Vanilla beans: I have strong feelings about vanilla. To me vanilla is one of the most overused flavours there is. Yes, it can play a great supporting role in many dishes, cookies and cakes but it can also be cloying and dull other flavours. For me, there should never be any vanilla in chocolate chip cookies or brownies and while a vanilla custard is heavenly, I am equally happy with a saffron, mahleb or tonka bean flavoured custard.  That being said, if you do use vanilla, go for the real deal – find big, fat and juicy vanilla beans. But also make sure you are making the most of each bean and not wasting any of that previous vanilla flavour. I like to think of vanilla beans as having 3 lives – the first one is where you scrape the vanilla beans from the pod into a cookie dough or cake mix. The second one is where you use vanilla bean to flavour a cream or a custard. And the third one is where you use that spent vanilla bean, once thoroughly rinsed and dried to either make your own batch of vanilla sugar (by simply resting it in a jar with plain sugar, which, over time, will take on a heady vanilla aroma and flavour) or homemade vanilla extract by filling a bottle with clear alcohol (e.g. vodka), and continuing to add more spent vanilla beans to the bottle over time to help infuse the alcohol.

• Wine (red, white and even sparkling wine) is one of the ingredients of one of my favourite Italian anise-scented cookies, Ciambelline al Vino. Beyond that, wine is obviously an excellent choice for poaching fruit but can also be turned into a simple syrup used to moisten cake layers for example. 

• Ganache: Given its dairy content, leftover ganache is best stored in the fridge. However, even there I suspect it won’t keep very long because it is a delicious alternative to Nutella spread on your toast, an excellent choice when making stuffed French Toast and, after a short stint in the microwave, is delicious poured over ice cream. And let’s not forget that melted into some hot milk it also makes delicious hot chocolate. 

• Small amounts of yoghurt, labneh, sourcream, creme fraiche can easily be added to most loaf cake recipes - e.g. you can typically replace half the amount of butter or oil in most loaf cake recipes with yoghurt and still achieve a delicious cake with a gorgeous tender crumb. Alternatively, they are the perfect addition when making whipped cream for extra stability and a more interesting flavour profiles thank to their slight acidity.