Molten Chocolate Cupcakes

1, Fill a muffin tin with 8 paper muffin cases.
2. Using a large mixing bowl, add in the butter, baking powder, sugar, egg, flour and cocoa. Whisk with an electric mixer until smooth.
3. Spoon half of the batter into the cups and make an indentation in the middle with a teaspoon or your finger. Break the chocolate up evenly and add a square inside the space. Fill with the rest of the batter on top.
4. Bake at 375ºF for about 15 minutes, or until the edges are baked and the centre is slightly soft. Let rest for 2 minutes and sprinkle with a dusting of icing sugar. Serve.