Heat the oven to 180C/160C fan/gas 4. Oil a 20 x 30cm traybake tin and line with baking parchment. Whisk the oil, sugar, eggs and milk together in a large bowl. Sieve over the flour, cocoa, malted milk powder and bicarbonate of soda, then fold the dry ingredients into the wet until well-combined. Pour the batter into the prepared tin and bake for 30-35 mins until the sponge has risen and springs back when gently pressed – a skewer inserted into the middle should come out clean. Set the tin on a wire rack and leave to cool completely.

While the sponge cools, make the buttercream. Beat the butter, icing sugar, malted milk powder, vanilla and 1 tbsp boiling water from the kettle together using an electric whisk until pale and fluffy. Spoon the buttercream over the cooled cake and gently spread to the edges using a spatula or palette knife. Scatter over the bashed chocolate balls, then decorate with the chocolate bunnies and halved chocolate eggs before serving. Will keep in an airtight container for up to three days.