1/2 cup (1 stick) butter
1 cup flour
1 1/3 cups plus 1/4 cup granulated sugar (divided)
1 teaspoon baking powder
1/2 teaspoon salt
3 teaspoons vanilla extract (divided)
4 eggs (divided)
8 ounces cream cheese (at room temperature)
1 1/2 cups sour cream (divided)
Grease and flour bottom of 12 x 8-inch baking pan.
In small bowl, combine butter, flour, 2/3 cup of the sugar, baking powder, salt, 1 teaspoon vanilla extract and 2 eggs. Beat at medium speed with electric mixer until well blended. Spread into bottom of pan.
Preheat oven to 325 degrees F.
Using same bowl, combine cream cheese, another 2/3 cup sugar, another 1 teaspoon vanilla, remaining 2 eggs and 1/2 cup sour cream. Beat at medium speed until smooth and creamy. Pour over batter in pan. Bake 30 minutes or until done.
While cake is baking, make topping by combining remaining 1 cup sour cream with remaining 1/4 cup sugar and remaining 1 teaspoon vanilla extract.
When cake is done, remove from oven and spread with topping. Immediately loosen from sides of pan with thin metal spatula. Cool, chill at least 4 hours before serving.