Preheat oven to 350°.
Combine first 4 ingredients in a mixing bowl; mix well. Press into an 8-inch square baking pan coated with cooking spray.
Bake at 350° for 12 minutes; cool slightly on a wire rack.
Whisk together eggs and next 7 ingredients until smooth. Pour egg mixture over prepared crust. Bake at 350° for 20 to 22 minutes or until set. Cool completely on wire rack. Sift powdered sugar evenly over top. Cut into bars.