In a double boiler, melt the chocolate, instant coffee and milk together.
Preheat the oven to 170 degrees.
Sieve the flour, baking powder, and salt in a bowl. Mix well.
Mix softened butter with both white and brown sugar.
Beat the egg separately, and add it to the butter mixture in 3 times. Mix well after each addition.
Add flour mixture and melted chocolate to the butter-egg mixture bit by bit. Mix well after each addition.
Add extra chunks of chocolate if you prefer.
Put the mixture evenly to 6 muffin tins.
Bake in the oven for 15-20 mins until a skewer came out clean.
