For the brownies you'll need...
Melt the butter and chocolate together.
Blend together all other ingredients except flour in a separate bowl.
Combine the chocolate/butter mixture with the egg/sugar mixture. Stir in oat flour.
Line a 9"x13" pan with a parchment sling.
Pour your batter into the prepared pan and top with chopped chocolate.
Bake until a toothpick inserted into the center comes out clean.