Melt milk chocolate in microwave at high heat for about 20-30 seconds, leave to cool.
Sift self raising flour and baking powder in a bowl. Add in remaining ingredients till mixture just combined. (mixture looks thick at this stage, do not overmix).
Distribute flour mixture evenly into 6 muffin cups.
Bake at 180C in preheated oven for about 30 minutes or skewer insert into the center comes out clean.
Best to serve warm.
Recipe by Anncoo Journal at https://www.anncoojournal.com/double-chocolate-muffins/