Melt butter and broken chocolate squares together. Mix well to make a smooth ganache. Cool it completely.
To the chocolate ganache add flour, baking powder, corn flour, salt, sugar, chocolate chips and chopped walnut. Mix well.
Add as little milk as required and make a soft dough.
Grease a baking tray very well. Preheat oven at 175C.
Using a tablespoon scoop out dough and press slightly. Arrange on the greased baking sheet. Give enough spacing as cookies really spread a lot.
Press some chocolate chip and walnuts on each brookie. Bake for 8-12 minutes till the edges turn slightly crispy, the top cracks and the cookies turn slightly hard to touch. Do not bake for more than 12 minutes. Cool for 15 minutes before removing from tray. Serve as snack.
Notes
1. I used a tablespoon to scoop out for uniform sized cookies 2. You can leave out walnuts if you wish