When it comes to food and preparing meals, there are some behaviours we are so accustomed to that we do them without a second thought. These include the ingredients we discard when cooking.

But many of these ingredients can be the basis of a delicious meal, saving you money (because you can now use what you were going to throw away) and saving the environment by reducing the amount of food waste you produce. 

One of these foods is aquafaba. If that sounds daunting, it's not. Aquafaba is simply the water from a can of chickpeas or butter beans. And what you probably don't know is that you can use it as an egg substitute to create dishes like meringue, chocolate mousse, doughnuts or French toast. 

When whisked, aquafaba takes on the same consistency as whisked egg whites, turning into that fluffy cloud-like mixture which stands in soft peaks when you take out the whisk. And once you've done that, you can use it like you would any other whisked egg white mixture. It's also vegan so it opens up delicious desserts like meringues to those who don't eat animal products.  

One amazing way to use aquafaba is to make it into a rich and indulgent chocolate mousse. To do that you will need the following: 

• 2 tbsp extra virgin olive oil, plus extra for drizzling

• 2 tsp maple syrup

• 1–2 pinches of salt

• 140ml aquafaba (liquid from a tin of chickpeas, at room temperature)

To make the mousse, all you have to do is follow these steps: 

1. Place a heatproof bowl over a saucepan of simmering water and slowly melt the chocolate, making sure the bowl doesn’t touch the water.

2. Once melted, remove from the heat and stir in the olive oil, maple syrup and a pinch of salt.

3. In a clean, grease-free bowl, whisk the aquafaba until stiff peaks form (this can take around five minutes).

4. Stir a spoonful of the whipped aquafaba into the chocolate mixture to lighten it. Then gently fold the chocolate mixture into the remaining whisked aquafaba using a metal spoon, being careful not to knock out the air.

5. Spoon the mixture into four small glasses and refrigerate for at least 1 hour to set.

6. Before serving, top with cherries, a drizzle of extra olive oil, and a pinch of salt. You can also add toasted hazelnuts or crème fraîche as desired.

Another way to use it is to make merignues. To do that, again you just need the aquafaba from the tin, plus around 120g of caster sugar. Again, whisk the aquafaba until stiff peaks form, then start slowly adding the sugar a bit at the time until you have a glossy and silky mixture. Then drop the mixture a spoonful at a time on to a baking tray or two and bake in the oven for around an hour or until it's a pale coffee colour and the bottom sounds hollow when you tap it. 

From there, you can eat the meringue as you please, or even turn it into a simple but delicious Eton mess — you can see how to do that here. 

Carleigh Bodrug, a best-selling food author who specialises in minimising food waste, says aquafaba is "liquid gold". She told the Zoe podcast: "I feel like it's quite popular in maybe a niche group, probably a baking crowd, but this is really something you should never throw away.

"If you're opening up a can of chickpeas, you were just going to pour that down the drain. So the potential is limitless for this ingredient that costs you nothing."

Zoe's US medical director, gastroenterologist Will Bulsiewicz, told the same podcast that aquafaba has health benefits too. He said: "The chickpeas are soaking in this water. And... anything that is what we would describe as water soluble... will start to leak from the chickpea into this water. 

"So what we find is that there's both fibre and starches that have come from the chickpeas. And there was a new study... they looked at the aquafaba and found that there were around 80 unique types of fibre and that these 80 unique types of fibre in the aquafaba were actually specifically feeding the beneficial gut bacteria.

"These are the beneficial gut bacteria that many people are paying a lot of money for in a probiotic. And basically what we're saying is the part that you discard, that people are pouring down their drain, you could be consuming that, making a delicious meringue that has 80 types of fibre that feed and give you those probiotic bacteria."