Heat the oven to 180 degrees.
Put butter, sugar, chocolate (30 grams), cocoa and milk into the pan. Bring mixture to a boil and remove from heat.
When the mixture has cooled, add the egg and beat a little.
Add flour and baking powder, mix.
Chop the remaining chocolate.
Fill the form with a dough for 2/3, then drown in it pieces of chocolate.
Bake 25 minutes.