Chocolate and chestnut macarons

Method

1. Heat the oven to 150°C/gas 2 (NB don’t use the fan setting) and line 2 large baking sheets with baking paper. Using a 3cm round cookie cutter as a guide, draw 40 circles with at least 2cm space between each across both pieces of paper. Put the piping bag with the nozzle attached in a tall jug.
2. Sift the icing sugar, ground almonds and cocoa powder into a large bowl. It’s important to sift everything thoroughly, so repeat this process twice more.
3. Put the egg whites and caster sugar in a stand mixer with a whisk attachment and whisk for 5 minutes until thick, glossy and can be held upside-down without falling out. Carefully sift the cocoa mixture over the top, then fold in very gently with a spatula using a figure-of-eight motion until combined and glossy.
4. Transfer the mixture to the piping bag, then pipe swirls into the drawn circles, staying within the lines. Bake for 30 minutes, then leave to cool for 10 minutes. Peel them off the paper carefully and transfer to a wire rack to cool completely.
5. For the filling, whip all the ingredients together until smooth. Use the filling to sandwich 2 of the meringue circles together. They are best eaten the same day as the macaron softens over time, although they’ll still be perfectly devourable for a few days afterwards.