In a large bowl, combine the flour, 1/4 cup sugar, baking powder and salt; cut in butter until mixture resembles coarse crumbs. Press onto the bottom and 1 in. up the sides of a greased 13-in. x 9-in. baking dish. , Arrange peaches over crust. Combine cinnamon and remaining sugar; sprinkle over peaches. Bake at 400° for 15 minutes., Meanwhile, in a small bowl, combine egg yolks and sour cream. Spread evenly over peaches. Combine sugar and cinnamon; sprinkle over top. , Bake 30-35 minutes longer or until set. Serve warm or cold. Store leftovers in the refrigerator.