Best Chocolate Brownie

Ingredients

1/4 cup flour
2 tablespoons unsweetened cocoa
1 teaspoon baking powder
1/2 teaspoon salt
9 ounces bittersweet chocolate
4 tablespoons butter
3 eggs
3/4 cups granulated sugar
1 teaspoon pure vanilla extract
1/4 cup sour cream
1 coarsely
2 cake
10 secon sour cream

Instructions

NOTES : adapted from Marcel Desaulniers, Death by Chocolate