Lingkan Reang
Preheat oven to 180°C and line a 13x9 inch baking tray with parchment paper.
Melt butter, then mix in sugar, cocoa, vanilla, egg, salt, baking powder, and flour.
Stir in chocolate chips and pour the batter into the tray.
Bake for 25-30 minutes, then cool completely.
Slice into triangles and prepare buttercream by mixing butter, icing sugar, vanilla, and food colour.
Pipe buttercream onto the triangles to decorate, then add sprinkles.