Step 1

Break the chocolate into smaller chunks and place it in a glass or metal bowl. Place the bowl over the water bath and allow the chocolate to heat up very SLOWLY and make sure the water does not touch the bottom of the bowl (that's important as chocolate is very sensitive to high temperatures). Once the chocolate has melted, take the bowl off the heat and allow it to cool down a little.

Step 2

Open your tin of chickpeas and drain the chickpea water into large glass bowl. Aquafaba should not be fridge-cold as it will make chocolate seize when added. The bowl and the utensils you'll use to whip aquafaba need to be completely grease-free as even the tiniest grease residue can prevent aquafaba from reaching stiff peaks.

Step 3

Add a teaspoon of acid (neutral vinegar, lemon or lime juice) to the chickpea water to stablise the aquafaba.

Step 4

Using an electric egg whisk, whip the chickpea water into stiff peaks - this is SUPER important as otherwise your mousse will deflate completely once the chocolate has been added. The best way to check if you have achieved stiff peaks is to invert the bowl with whipped aquafaba. If aquafaba slides down even a tiny bit, you are not there yet - keep on whipping until it does not move at all. I used an old, hand-held whisk and it took me about 15 minutes to get stiff peaks. If you are a lucky owner of a stand mixer, it will happen quicker. The good news is that (as opposed to egg whites) aquafaba cannot be overwhipped.

Step 5

OPTIONAL STEP (depends on your plate and on how sweet your chocolate is): Once you reach stiff peaks, start adding sugar, bit by bit, whipping the whole time. If sugar has caused the stiff peaks to perish, whip the mixture until you get stiff peaks again. I have not tested with other types of sugar and it does tend to ruin aquafaba meringues, for example, so experiment at your peril.

Step 6

Check that the chocolate has cooled down sufficiently - it should not be warm to the touch or else chocolate may seize and you will end up with grainy mousse.

Step 7

Gently and gradually fold melted chocolate into whipped aquafaba using a silicone spatula and a gentle folding motion. Do not worry if your fluffy mixture deflates a bit once the chocolate has been added - that's perfectly normal - but it should not turn soupy. By the time you've added all of your melted chocolate, the mousse MAY have more of a pourable than spoonable consistency.

Step 8

Add chilli powder if using and mix well. Divide the mixture between 4 glasses. Gently stir the mixture between putting it into individual glasses as a bit of melted chocolate tends to drop to the bottom sometimes.

Step 9

Put glasses into the fridge overnight for the mousse to set.