The most extraordinary Southern Caramel Cake made by preheating oven to 350°F greasing and lining two 9-inch pans whisking 2 1/2 cups flour 2 tsp baking powder 1/2 tsp baking soda and 1/2 tsp salt beating 1 cup softened butter and 1 1/2 cups packed dark brown sugar medium-high 2 to 3 minutes light and creamy adding 4 room temperature eggs one at a time then 2 tsp vanilla stirring 3/4 cup room temperature sour cream and 1/2 cup room temperature milk alternating flour in 3 additions with sour cream milk in 2 additions beginning and ending with flour just combined dividing between pans baking 28 to 32 minutes cooling then for frosting melting 1 cup butter in heavy-bottomed saucepan adding 2 cups packed dark brown sugar and 1/2 cup heavy cream stirring combined bringing to full rolling boil cooking stirring constantly to 235°F softball stage 3 to 5 minutes removing from heat stirring in vanilla and salt cooling 15 minutes adding 2 to 3 cups sifted powdered sugar two cups at a time beating smooth and spreadable assembling layers with warm caramel frosting between and frost exterior immediately as frosting firms while cooling. A completely perfect moist dark brown sugar sour cream real cooked Southern caramel frosting celebration cake recipe.