Combine spaghetti noodles, spaghetti sauce and ground beef in a large bowl; set aside. Melt butter in a saucepan over medium heat; add flour, parmesan cheese, salt and garlic powder, stirring constantly until smooth and bubbly. Add evaporated milk and one cup cheddar cheese; stir until thickened. Pour half of spaghetti noodle mixture into a greased 13x9" casserole dish and pour cheese mixture over top. Pour remaining noodle mixture into dish; top with remaining 2 cups cheddar cheese. Bake at 350* for 25-30 minutes.