1/3 cup unsweetened cocoa powder
2 1/2 cups blueberries
1/3 cup unsweetened cocoa powder
Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13 inch pan.
In a large bowl, mix together cocoa powder and blueberries until well blended. Stir in cocoa until nearly blended. Pour half of filling into each pan.
Bake in the preheated oven for 1 hour, or until almost no streaks remain. Cool completely before turning out of pan. Place in microwave oven for 2 to 3 minutes. Frost top and sides of pan with Frosting (see Cook's Note for instructions).