Preheat the oven to 350°F.
Layer a baking sheet with parchment paper.
In a pot melt together 9 oz of chocolate with butter. Set aside. Chop the remaining 2 oz of chocolate and set aside.
Whisk on high speed for 3 minutes.
Add the flour mixture to the egg mixture.
Change the mixer attachment to paddle attachment. Mix on low speed just until combined.
Bake for 10 minutes at 350°F.