Makes 12 muffins
Muffin tin lined with muffin cases, grease with butter anywhere that isn't covered by the muffin cases
180°C | 350°F | Gas Mark 4
25 minutes (or until a toothpick inserted in comes out almost clean. But 25 is spot on for my oven)
Divide mixture evenly between cases. Sprinkle on reserved chocolate chips.
Bake until done.
Leave in pan to cool for at least 10 minutes before moving to a wire cooling rack.