Preheat the oven to 400°F.

Put all the cupcake ingredients except for the milk into the food processor and blitz to combine. Pulse again, adding milk down the funnel to form a batter with a soft, dropping consistency. Spoon into the baking cups in their pan and put in the oven to cook for about 20 minutes. When ready, remove from the oven and leave in the pan to cool for 5 minutes before turning out onto a wire rack.

When they’re completely cold, get on with the icing. Melt the chocolate and butter in the microwave or in a double boiler, and after it’s cooled a little, stir in the sour cream. Gradually beat in the sifted confectioners’ sugar. And if the consistency isn’t right for icing, add either hot water to thin or more sifted sugar to thicken. Spread roughly and generously over the top of each cupcake, and then dust sparingly with cocoa, by pressing a little through a tea strainer, so that they look like little cups of chocolate-dusted cappuccino.