Pre-heat oven to 180C. Sieve the dry ingredients together; self-raising flour, baking powder and cocoa powder.
Weigh out the sugar. Add to the dry ingredients. Use a whisk to thoroughly mix everything together.
Melt semi-sweet chocolate with butter in a bowl over a boiling pot of water. Leave to cool.
Beat the eggs and sour cream together.
Add vanilla to the milk.
Pour sour cream-egg mixture to dry ingredients along with milk-vanilla.
Give it mix with spatula, add the melted butter and chocolate.
Give everything a good mix with the spatula to make sure there is no raw flour.
Add chocolate chips and give it a final stir.
Prepare muffin tray lined with cups. Spoon batter to cups. Drop some chocolate chips on top.
Bake in the oven for about 30 mins or till the skewer comes clean.
Leave to cool before eating.