Kid-Pleasing Spaghetti

Ingredients (10)

• 1-1/2 pounds ground beef
• 1 medium onion, chopped
• 2-1/2 cups spaghetti sauce
• 8 ounces spaghetti, cooked and drained
• 3 tablespoons butter
• 2 tablespoons all-purpose flour
• 1/2 teaspoon salt
• 1-1/2 cups whole milk
• 1-1/2 cups shredded cheddar cheese, divided
• 1/4 cup grated Parmesan cheese