Sloppy Joe Macaroni and Cheese

Found this on the line of the grocery store. My kids grabbed a hold of this one and wanted me to make it.

• Ready In: 55 mins
• Serves: 6

Ingredients

• 3  tablespoons butter
• 8  ounces cavatappi pasta
• 1  small onion, chopped
• 1  lb  extra lean ground beef
• 1 (8 ounce) can tomato sauce
• 1 (1 1/3ounce) envelope  sloppy joe seasoning mix
• 3  cups milk
• 1  tablespoon yellow mustard
• 3  tablespoons all-purpose flour
• 12  ounces  shredded cheddar cheese (3 cups)
• 1⁄4 cup  seasoned dry bread crumb

Directions

1. Preheat oven to 375°F
2. Coat 2-qt. baking dish with 1 Tbs. butter.
3. Cook pasta according to package directions; drain.
4. Meanwhile, in large skillet, heat 1 Tbs. butter over medium heat.
5. Add onion; cook until softened.
6. Add beef; cook until lightly browned, 3 minutes.
7. Stir in sauce, 1 cup water and seasoning mix; cook 5 minutes.
8. Combine milk and mustard; bring to boil.
9. Reduce heat to low and whisk in flour; cook, whisking, until smooth and slightly thickened.
10. Stir in 2 cups cheese and pasta.
11. Spread meat mixture in baking dish; top with pasta mixture, then remaining cheese.
12. Melt remaining butter; stir in breadcrumbs.
13. Sprinkle over cheese.
14. Place baking dish on baking sheet.
15. Bake until golden, 25-30 minutes.