Preheat oven to 375°.
Spray a 9" round baking pan with gluten free baking spray or grease with butter and dust with all purpose flour.
In a large bowl add butter and melt in microwave, 1 minute.
Remove and add chocolate return bowl to microwave and cook an additional minute.
Stir chocolate butter mix to make sure chocolate is completely melted.
Add granulated sugar and vanilla extract to chocolate mix and stir.
Separate eggs, add yolks to chocolate mix and egg whites to a separate medium sized bowl.
Add Almond Meal to chocolate mix and stir.
With an electric mixer beat egg whites until peaks start to form and then add cream of tarter and mix an additional minute.
Add egg whites to chocolate mix and fold whites into chocolate.
Pour into prepared pan and bake 30-35 minutes. Until toothpick comes out clean.
Center of cake will fall a bit.
Once cake is cool, flip upside down onto a plate and sprinkle with powdered sugar and top with berries if using.