Dessert

Melt butter, caster sugar and cocoa over a pan of simmering water until smooth
Whisk in beaten egg for 2–3 minutes until the mixture thickens
Stir in shredded digestive biscuits, desiccated coconut and almonds, press into the base of a lined 20cm square tin and chill 10 minutes
Whisk butter, double cream and custard powder until light and fluffy
Gradually add icing sugar and beat until fully incorporated
Spread the custard icing over the chilled base and chill at least 10 minutes until no longer soft
Melt dark chocolate and butter together in the microwave until smooth
Spread the melted chocolate over the chilled bars and return to the fridge until fully set (about 2 hours)
Remove the slab from the tin and slice into squares to serve