1. Cook pasta according to package directions. Drain. Set aside.
2. In medium saucepan cook ham in 3 tablespoons butter over medium-high heat until just beginning to brown. Use slotted spoon to remove ham from pan, reserving drippings in pan. Drain ham on paper towels. Add onion to drippings. Cook and stir over medium heat until tender.
3. Stir in flour, salt, mustard and pepper. Cook, stirring constantly, for 2 minutes. Gradually whisk in milk and pepper sauce. Bring to boiling, stirring constantly. Reduce heat. Simmer, uncovered, for 10 minutes, stirring frequently. Remove from heat.
4. Add cheddar cheese and American cheese, a little at a time, stirring until melted after each addition. Stir in pasta and ham. Transfer to 8 x 8 x 2-inch baking dish.
5. In small bowl toss together SUNSHINE CHEEZ-IT Original snack crackers and 1 tablespoon butter. Sprinkle over pasta mixture. Bake, uncovered, at 400°F for 15 to 20 minutes or until heated through. Let stand for 10 minutes.