Kielbasa Bake with sauce

nonstick cooking spray 8 ounces dried rigatoni pasta or 8 ounces penne pasta 2 cups milk (not fat-free) 2 tablespoons all-purpose flour 1 cup shredded cheese[...]

1 lb rigatoni pasta 2 tablespoons olive oil 1 large onion , sliced 1/4 cup all-purpose flour 1 quart milk 3 cups extra-sharp cheddar cheese 1 teaspoon hot[...]