Ingredients
1 stick of butter, at room temperature
2 cups sugar
3 eggs, separated
16 ounces sour cream
1 1/2 teaspoons vanilla extract
3 cups all-purpose flour
1 1/2 teaspoons baking soda
1 teaspoon baking powder
1/2 teaspoon salt
1 teaspoon cinnamon
12 ounces chocolate chips
Instructions
Have ready a greased 9-by-13-inch rectangular baking pan. Set the oven at 350 degrees.
In a large bowl, cream butter and 1 1/2 cups sugar, then mix in the egg yolks, sour cream, and vanilla.
In a medium bowl, sift together the flour, baking soda, baking powder, and salt. Stir into the butter mixture.
Beat the egg whites until they hold stiff peaks, then fold into the batter. In a small bowl, mix the cinnamon with the remaining 1/2 cup of sugar and the chocolate chips.
Pour half of the cake batter into the pan. Sprinkle the top with half of the cinnamon-sugar mixture. Pour remaining batter on top, then cover that with the remaining cinnamon-sugar mixture.
Bake 40-50 minutes or until a tester comes out clean.
