Step 1: Preheat the oven

Preheat your oven to 180°C (350°F). Grease and line the base of two round cake tins with parchment paper.

Step 2: Make the cake batter

In a large mixing bowl, beat the softened butter and caster sugar together until pale and fluffy. Add the eggs one at a time, beating well after each addition. Sift in the flour, cocoa powder, and baking powder, and fold gently until combined. Stir in the milk to loosen the batter.

Step 3: Bake the cakes

Divide the batter evenly between the prepared cake tins and smooth the tops. Bake in the preheated oven for 20-25 minutes, or until a skewer inserted into the center comes out clean. Let the cakes cool in the tins for 10 minutes, then turn out onto a wire rack to cool completely.

Step 4: Prepare the frosting

In a mixing bowl, beat the softened butter until creamy. Gradually add the sifted icing sugar and melted chocolate, beating until smooth. Add 1-2 tablespoons of milk to achieve a spreadable consistency.

Step 5: Assemble the cake

Place one cake layer on a serving plate and spread a generous layer of frosting over the top. Place the second cake layer on top and spread frosting over the top and sides of the cake.

Step 6: Decorate

Sprinkle the top with your chosen decorations, such as sprinkles, candies, or chocolate shavings. For an extra festive touch, use fresh fruit or edible flowers.

Step 7: Serve

Slice and serve the cake at room temperature. Store any leftovers in an airtight container.