Tuna Broccoli Casserole

1/2 cup Divided margarine
1 medium Chopped onion
1/4 cup Cornstarch
3 cups Milk
1/4 tsp Hot pepper sauce
2 Chicken flavor bouillon Cubes
2 can (6.5-oz each) drained and Flaked tuna
1 pkg (10-oz) frozen chopped Thawed broccoli
8 oz Elbow macaroni cooked 6 Minutes and drained
1 1/4 cups Shredded cheddar cheese Divided
1/2 cup Fresh bread crumbs

Spray 1 quart casserole with cooking spray. In 2 quart saucepan melt 1/4 cup of the margarine over medium heat. Add onion; saute 3 minutes. In small bowl stir corn starch, milk and hot pepper sauce until smooth; add to onions in saucepan. Add bouillon cubs. STirring constantly, bring to a boil and boil 1 minute. In large bowl combine sauce, tuna, broccoli, elbow macaroni and 1 cup of the cheese. Turn into prepared casserole. In small bowl combine bread crumbs, remaining 1/4 cup cheese and remaining 1/4 cup margarine, melted; sprinkle over casserole. Bake in 350 degree oven 25 minutes or until topping is lightly browned.