Preheat your oven to 180C/160C Fan and line a 9x9" baking tin with parchment paper!
Melt together your dark chocolate and unsalted butter until smooth in the microwave or in a bowl over a pan of simmering water. Leave to cool for a few minutes
Using an electric whisk/stand mixer, whisk your eggs and sugar together for 5 minutes or so on high speed, or until the mixture has doubled in volume, is alot paler, and leaves a trail for a few seconds when you lift the whisk out.
Pour in the chocolate/butter mix and peppermint extract and fold through very carefully.
Add in the flour and cocoa powder and fold through carefully again.
Add in the Mint Aero and chocolate chips and fold in. Pour the mixture into the tin!
Bake in the oven for 25-30+ minutes. Sometimes it can take longer.
Leave to cool in the tin!
To decorate your brownies if you fancy it... melt your chocolate and drizzle over the brownies, and add sprinkle over chopped pieces of Mint Aero!
Then, if you want, put them in the fridge for a couple of hours to help 'set' them, and then enjoy!
Try and freeze the mint aero for at least an hour before baking, but it is not essential.
If your brownies are taking much longer than stated to bake, your oven may have been the wrong temperature, or you overmixed your batter. Keep adding on 5 minutes till they're done and cover with foil if need be!
The recipe has been updated in September 2020, the original recipe was the same (195g chocolate/butter) apart from it had a frosting on top. If you would still like to make the frosting it was 125g unsalted butter, 250g icing sugar, 1tsp peppermint extract and a small amount of green food colouring!