Preheat the oven to 180C or 356F. Melt the dark chocolate and butter in a small bowl or jug
In a separate bowl whisk the eggs and sugar until they start to foam and become fluffy
Combine the egg mixture with the chocolate mixture
Sieve the cocoa powder and flour into the mixture and stir slowly so you don’t knock all the air out of it.
Roughly chop the milk and white chocolate into small chunks (chocolate chips can also be used instead) and add them to the brownie batter.
Pour the batter into a square greased baking tin and bake for 26mins
Remove from the oven but make sure to leave them in the tin until completely cool.
Cut into squares and enjoy!