Heat the oven to 200C/180C fan/gas mark 6. Butter a pan or soak a sheet of baking parchment with water, then crumple it and wring it out. Use it to line a 20cm pan.

Create a double boiler by bringing a medium pan filled with about an inch of water to a simmer, then turn the heat to as low as it will go. Place a heatproof bowl, that's just big enough to sit on top, onto the pan and make sure the bottom of the bowl does not touch the water. Put the nut butter and cacao liquor buttons into the bowl. Let the chocolate sit for 1-2 mins to melt slightly, then stir the chocolate every 1-2 mins until it is completely melted with the nut butter. Remove the bowl from the heat.

Combine almond flour, cocoa powder, sweetener, baking powder, baking soda and mix well. Mix in the egg to fully combine.

Add the apple cider vinegar and soya milk to the melted chocolate and nut butter mixture, and mix well. Don’t worry if it looks like the chocolate has seized, it will come together once you’ve mixed it thoroughly. Combine your wet and dry ingredients and mix until fully incorporated.

Fold in the courgettes, then carefully pour the batter into the prepared tin. Bake for 10 mins, then reduce the temperature to 180C/160C fan/gas mark 4 and bake for 10-15 mins more. It is ready when a toothpick inserted in the middle comes out a bit sticky but without batter clinging to it. Remove from the oven and leave to cool completely before cutting. Cool the brownies completely to room temperature.

Before cutting the brownies, dip a knife in hot water, submerging the blade completely. Let the knife sit in the water for several minutes to make the blade hot. Keep dipping the blade and drying it between each cut you make into the brownies. Will keep chilled for up to three days.