Preheat oven to 160°C Fan / 180°C / 350°F / Gas Mark 4. Line a cupcake tin with black cupcake cases.

In a large bowl, whisk butter and sugar together until light and fluffy.

Add eggs and vanilla extract. Mix until smooth.

Add buttermilk, cocoa powder, bicarbonate of soda, red food colouring, and self-raising flour. Mix until just combined.

Divide the batter between cupcake cases, filling each about two-thirds full.

Bake for 20–25 minutes or until a skewer comes out clean. Cool completely on a wire rack.

Use a cupcake corer or small knife to remove the center of each cupcake.

Fill each hole with strawberry or raspberry jam using a piping bag or spoon.

For the buttercream, beat butter alone for 2 minutes until soft.

Add icing sugar, milk, vanilla extract, and a little pink food colouring. Beat until smooth and creamy. Adjust with more milk if too stiff.

Fill a piping bag with the frosting and use a round nozzle to pipe a line down the middle, then squiggly lines on both sides to form “brain” shapes.

Store in an airtight container at room temperature and enjoy within 3 days.