Preheat the oven to 180°C (350°F/Gas 4). Line 42 x 30 ml (1 fl oz/ cup) capacity mini-muffin holes with paper cases.
Sift the flour, baking powder and cocoa together into a bowl.
Place the butter, sugar and vanilla extract in the bowl of an electric mixer and beat on medium speed for 2–3 minutes or until light and creamy. Add the eggs, one at a time, beating well after each addition and scraping down the sides of the bowl as required. Add the flour mixture, in 2 batches, alternating with the milk. Add the chocolate chips and mix until just combined.
Transfer the batter to a large piping bag fitted with a 3 cm (1¼ inch) plain nozzle and pipe into the cases until three-quarters full.
Bake for 10–11 minutes or until just cooked and they spring back lightly to the touch. Cool for 1–2 minutes in the tins, then turn out onto wire racks to cool completely.
To make the cookie crumbs, place all of the ingredients in a bowl and combine well. Set aside.
To make the sauce, place the chocolate, cream and butter in the top of a double boiler over medium heat and stir until melted and smooth. Leave to cool slightly.
To make the frosting, place the eggwhite, sugar and cream of tartar in the top of a double boiler over medium heat and whisk for 3 minutes or until the sugar has dissolved and the mixture is warm. Remove from the heat, add the vanilla extract and, using electric beaters, beat for 6–7 minutes or until stiff peaks form. Immediately transfer into a piping bag fitted with a 1 cm (½ inch) plain nozzle and pipe onto the cupcakes. Lightly toast the frosting with a kitchen blowtorch, then drizzle each cupcake with the sauce and sprinkle with the crumbs.
MAKES 42
180 g (6 oz) plain (all-purpose) flour
1 teaspoon baking powder
30 g (1 oz/¼ cup) cocoa powder
150 g (5½ oz) unsalted butter
150 g (5½ oz) caster (superfine) sugar
1 teaspoon natural vanilla extract
3 eggs
3 tablespoons milk
50 g (1¾ oz/ cup) mini milk chocolate chips
COOKIE CRUMBS
2 wheat digestive biscuits, finely crushed
¾ teaspoon caster (superfine) sugar
¼ teaspoon ground cinnamon
CHOCOLATE SAUCE
85 g (3 oz/½ cup) mini milk chocolate chips
3 tablespoons pouring (single) cream
1 teaspoon unsalted butter
MARSHMALLOW FROSTING
3 eggwhites
165 g (5¾ oz/¾ cup) caster (superfine) sugar
¼ teaspoon cream of tartar
½ teaspoon natural vanilla extract