Macaroni and cheese casserole

3 tbsp. butter
2 tbsp. flour
1 tsp. salt
1/2 tsp. dry mustard
1/4 tsp. pepper
1 1/2 c. milk
2 c. shredded Cheddar cheese
7 oz. elbow macaroni, cooked and drained

TOPPING:

3 tbsp. butter
1/2 c. dry bread crumbs

Melt butter in 1 1/2 quart casserole in high about 30 seconds. Blend in flour, salt, mustard, and pepper. Stir in milk. Microwave on high until thickened, about 4 to 6 minutes. Stir once or twice during cooking. Stir in shredded cheese. Microwave on high to soften cheese, 30 seconds to 1 minute. Stir in cooked macaroni.

TOPPING: Place 3 tablespoons of butter in small bowl, microwave at high until melted about 30 seconds. Stir in bread crumbs. Sprinkle over casserole. Microwave at medium-high until heated through, 5 to 7 minutes. If using microwave that does not rotate, turn casserole once during last cooking time.