Cook noodles as directed on package. Drain and rinse.
Cut broccoli into bite sized pieces.
In a saucepan, melt butter over medium heat. Add onions and cook for about 1 minute. Add flour, dry mustard, salt and pepper. Stir and cook constantly for 1 minute. Add milk slowly, stirring constantly. Cook over medium-high heat until thick and smooth.
Add cheese and stir until melted.
In a large bowl, lightly combine noodles, ham, broccoli and sauce. Pour mixture into greased 11x7 casserole.
Bake at 375° for 20-25 minutes or until casserole is bubbly and heated through.
