In 12-inch nonstick skillet, cook beef over medium-high heat, stirring frequently, until thoroughly cooked. Drain.
Reserve 2 tablespoons onions for garnish; stir remaining onions, the soup and salsa into beef. Heat to boiling. Reduce heat to medium-low; cook 5 minutes.
Stir in cooked pasta; cook 3 to 5 minutes, stirring occasionally, until thoroughly heated. Sprinkle with cheese; cover and cook just until melted. Sprinkle with reserved 2 tablespoons onions. Enjoy !
3. Stir tomato sauce, next 4 ingredients, and 1 tsp. salt into meat mixture. Bring to a simmer over medium-high heat, and cook, stirring occasionally, 2 minutes. Remove from heat.
4. Melt butter in a large saucepan over low heat. Whisk in flour, and cook, whisking constantly, 2 minutes. Gradually whisk in milk. Increase heat to medium, and cook, whisking constantly, 5 to 7 minutes or until thickened and bubbly. Stir in Parmesan cheese, pepper, and remaining 1/2 tsp. salt. Add sauce to pasta, stirring to coat.
5. Transfer pasta mixture to a lightly greased (with cooking spray) 13- x 9-inch baking dish. Top with beef mixture, mozzarella cheese, and breadcrumbs.
6. Bake at 350° for 20 to 25 minutes or until mixture is bubbly and cheese is melted. Let stand 10 minutes before serving. Enjoy it!