Good-Cooking - Mahogany Pound Cake

Ingredients

• 1 teaspoon easpoon baking powder
• 1/4 teaspoon baking soda
• 2 cups granulated sugar
• 1 cup firmly packed light brown sugar
• 3/4 cup butter, softened
• 6 eggs, separated
• 1 teaspoon vanilla extract
• 8 ounces sour cream