1 Preheat the oven to 180°C and grease a 23cm-25cm ovenproof skillet with some butter. Melt the butter and dark chocolate in a bowl over a saucepan of simmering water, stirring occasionally until smooth (2-3 minutes).
2 Remove from the heat, add the sugar, then add the eggs one at a time, mixing well between additions. Sift over the flour, cocoa powder and baking powder, add the salt and stir to just combine (don't overwork the dough or the brownie will become cakey). Stir in the milk chocolate and peanuts, reserving a little of both for garnishing. Spoon into the skillet and smooth the top. Dot with peanut butter and swirl with the tip of a knife, scatter with the reserved peanuts and milk chocolate and bake until set around the edges but still fudgy in the centre (15-20 minutes; a skewer inserted should have some wet mixture on it). Cool briefly so it's not too hot (5 minutes), then serve warm with the ice cream or cream.
