Heat oven to 350*. Spray 11 x 9" glass baking dish with Pam. Cook and drain noodles as directed.
Remove fat from beef. Cut into 3/4" pieces. Heat skillet over medium heat. Cook beef and salt & pepper in skillet 2-3 minutes, stirring occasionally, until beef is brown. Stir in onions & bell pepper. Cook 2 minutes, stirring occasionally. Pour into baking dish.
In bowl, beat broth and flour with wire whisk until smooth. Add to skillet, heat to boiling. Cook stirring constantly until mixture thickens; remove from heat. Stir in half & half and mustard. Spoon over beef mixture. Stir in cooked noodles.
Cover and bake 40 minutes. Sprinkle with cheese and bake uncovered about 10 minutes longer or until cheese is melted.