– 1 1/2 cups all-purpose flour
– 1 1/2 teaspoons double-acting baking powder
– 1 cup sour cream
– 1 teaspoon baking soda
– 1 stick (1/2 cup) unsalted butter, softened
– 1 1/3 cups granulated sugar
– 2 large eggs
– 1 teaspoon vanilla extract
– 1/3 cup firmly packed light brown sugar
– 1 teaspoon cinnamon
• In a bowl whisk together the flour, the baking powder, and a pinch of salt
• In another bowl stir together the sour cream and the baking soda.
• In a large bowl cream together the butter and 1 cup of the granulated sugar until the mixture is light and fluffy, add the eggs, 1 at a time, beating well after each addition, and beat in the vanilla.
• Stir in the flour mixture alternately with the sour cream mixture and stir the batter until it is combined well.
• Pour the batter into a buttered 10-inch round cake pan. In a small bowl stir together the remaining 1/3 cup granulated sugar, the brown sugar, and the cinnamon and swirl the sugar mixture into the batter.
• Bake the cake in the middle of a preheated 350°F. oven for 45 to 50 minutes, or until a tester comes out clean, transfer it to a rack, and let it cool.