Gluten free nonstick cooking spray
2 cups good quality all-purpose gluten free flour blend
2 tablespoons unsweetened cocoa powder
1 teaspoon baking powder
1/2 teaspoon baking soda
1/2 teaspoon kosher or fine sea salt
1/2 cup (1 stick) unsalted butter, at room temperature
3/4 cup sugar
2 large eggs, at room temperature
1 teaspoon pure vanilla extract
1 cup sour cream, at room temperature
1 cup semi-sweet chocolate chips, melted and cooled
8 ounces cream cheese, at room temperature
3/4 cup SunButter, any smooth variety
3 to 3-1/2 cups powdered sugar
1 tablespoon pure vanilla extract
Heat the oven to 350°F. Spray a 9-inch cake pan with cooking spray. Set aside.
In a mixing bowl, whisk together the flour, cocoa powder, baking powder and soda, and salt.
In an electric mixer, preferably fitted with a paddle attachment, beat the butter and sugar together until light and fluffy, about 3 minutes. Add the eggs, one at a time, beating well after each addition. Turn the mixer to low, beat in half the flour mixture, the sour cream, and finally the rest of the flour. Using a spatula, stir in the melted chocolate chips, making sure all ingredients are fully combined. Pour the batter into the prepared baking pan and bake for 45 minutes or until a toothpick inserted into the center comes out clean. Let cool in the pan for 10 minutes then transfer to a wire rack to finish cooling completely.
In an electric mixer, preferably fitted with a paddle attachment, beat the cream cheese and SunButter together until creamy. Add the powdered sugar, 1 cup at a time, and beat until the frosting reaches a spreading consistency. Beat in the vanilla. Refrigerate until ready to use.
To assemble, cut the cake in half horizontally. Place the bottom layer on a cake stand or platter. Spread some of the frosting on top, place the top layer on and frost the sides and top.