To make the brownie, preheat the oven to 175°C (340°F/Gas 3–4). Grease and line a 31 cm x 21 cm x 5 cm (12½ inch x 8¼ inch x 2 inch) cake tin with baking paper. Place the chocolate and butter in the top of a double boiler over medium heat and stir until melted and smooth. Add the sugars and stir until dissolved. Remove from the heat and cool slightly. Add the egg and vanilla extract and stir to combine. Sift the flour and cocoa together into a large bowl, add the chocolate mixture, combine well and stir in the walnuts.
Pour into the tin and bake for 25–30 minutes or until still fudgy and a skewer inserted into the centre comes out with moist crumbs. Cool completely in the tin.
Line 2 baking trays with baking paper. Using a small ice-cream scoop, scoop out balls of brownie onto the trays. Quickly roll each in the palms of your hands to shape into a neat ball. Insert a stick into each ball and refrigerate for 2 hours or until well chilled and firm.
Carefully dip each brownie pop in the melted chocolate and tap the stick on the side of the bowl while slowly spinning to remove excess chocolate. Roll each pop in the sprinkles to coat well. Stand in Styrofoam to dry. Serve immediately or store in an airtight container in the refrigerator for 3–4 days.
40 lollipop sticks
500 g (1 lb 2 oz) dark chocolate (70% cocoa solids), melted
chocolate sprinkles, for coating
WALNUT BROWNIE
300 g (10½ oz) dark chocolate (70% cocoa solids), finely chopped
185 g (6½ oz) unsalted butter, at room temperature
330 g (11¾ oz/1½ cups) caster (superfine) sugar
45 g (1¾ oz/¼ cup lightly packed) soft brown sugar
4 eggs, lightly beaten
2 teaspoons natural vanilla extract
150 g (5½ oz/1 cup) plain (all-purpose) flour
2 tablespoons cocoa powder
100 g (3½ oz/1 cup) walnuts, finely chopped