2 pounds yellow summer squash -- sliced
3/4 cup chopped onions
1 tablespoon light margarine
2 tablespoons all-purpose flour
1 cup skim milk
3/4 cup shredded lowfat cheddar cheese
1/2 teaspoon salt
1/4 teaspoon pepper
vegetable cooking spray
1/2 cup bread crumbs -- toasted
Cook squash and onion in a small amount of boiling water 10-12 minutes or until vegetables are tender. Drain; set aside.
Melt margarine in a medium heavy saucepan over medium heat. Add flour; cook 1 minute, stirring constantly. Gradually add milk; cook, stirring constantly, until mixture is thickened and bubbly. Remove from heat; add cheese, salt, and pepper, stirring until cheese melts. Add squash mixture; stir well.
Spoon squash mixture into a shallow 1 1/2 quart casserole coated with cooking spray. Sprinkle squash mixture evenly with bread crumbs. Bake at 350°F. for 20-25 minutes or until mixture is thoroughly heated.