25 g (1 oz) cocoa powder, sifted, pluse extra to serve
3 tablespoons mascarpone cheese
75 g (3 oz) white chocolate chunks or chips
50 g (2 oz) milk chocolate chunks or chips
crème fraîche, to serve
Line a 12-hole nonstick muffin tin with paper cupcake cases. Place all of the ingredients except the chocolate chunks in a large bowl and beat together with a hand-held electric whisk until creamy, then fold in the chocolate chunks.
Spoon the mixture into the prepared muffin tin and bake in a preheated oven, 200°C (400°F), Gas Mark 6, for 15 minutes, or until risen and just firm. Transfer to wire racks to cool slightly.
Serve warm with crème fraîche, dusted with cocoa powder.