Mix the flour and sugar, cut in the butter until it's crumbly.
Press into a greased 9x13 pan and bake at 350°F for 15 minutes.
For the filling, mix the rest of the ingredients except the powdered sugar until combined. Pour over hot crust and bake at 350°F for 20 minutes or until lightly browned around the edges and center is set.
Cool and sprinkle with powdered sugar. Cover and store in the refrigerator.