Preheat the oven to 350 degrees F. Lightly butter a 13x9 inch baking pan and set aside
Mix the flour and the cocoa powder in a large bowl and set aside..
Melt the butter in a large saucepan
Once the butter has melted, add the chocolate and heat stirring until fully melted.
Add both kinds of sugars and whisk until the sugar has dissolved.
Add the eggs two at a time whisking well after each addition.
Whisk in the vanilla extract.
Add the chocolate batter to the flour mixture and mix with a wooden spoon until there are no visible lumps.
Pour the brownie batter into the prepared baking pan and smooth it out with a spatula.
Place the donuts on top of the batter in a 4x3 pattern and gently push down until the donuts are halfway in the batter.
Bake in the oven for 30-35 minutes. Let cool for at least one hour before slicing with a sharp knife.