Cool spaghetti and drain. Add the spaghetti back to the pan you used. Add condensed cheddar soup and sauce, mix until blended. Stir in 2 cups of the cheese. Transfer to a small and shallow baking dish (about 9" x 8,5"). Spread the remaining 2 cups of cheese evenly over the top of the spaghetti mixture. Broil on low for about 10 minutes or until cheese is golden and browned.