1. Preheat oven to 350F. To prepare crust, beat butter in a heavy mixer until creamy. Add flour, sugar and salt and beat until dough forms. Press the crust into the bottom of a 9 x 13-inch baking dish. Bake 20 minutes.
2. While crust is baking, prepare the filling. Place all ingredients into a food processor or blender. Pulse until combined. Pour filling evenly over hot crust. Return to oven and bake 15-20 minutes or until filling is not jiggly. Cool completely. Dust with powdered sugar.