Preheat your oven to 160ºC (140ºC fan) and prepare two 8-inch cake tins by greasing and lining with parchment paper.

Melt the dark chocolate and unsalted butter in a microwave-safe bowl, stirring every 30 seconds until smooth.

Dissolve coffee granules and malt powder in 100ml boiling water in a small mug for the flavor mix.

Combine plain flour, cocoa powder, baking powder, bicarbonate of soda, caster sugar, and light brown sugar in a mixing bowl.

Whisk together eggs and buttermilk in a separate bowl, then gradually add the melted chocolate mix and coffee-malt blend.

Divide batter into prepared tins and bake for 45-50 minutes until a skewer comes out clean. Cool in tins for 10 minutes before transferring to wire racks.

Beat softened unsalted butter until creamy, then sift in icing sugar and malt powder, adding boiling water as needed for consistency.

Once cool, layer the cake on a plate, spreading chocolate spread and buttercream between layers, then top with remaining buttercream.

Decorate the top with buttercream and adorn with whole and crushed Maltesers.