Homemade Mac n' Cheese

2 cups uncooked macaroni
1/4 C margarine
1/4 C flour
4 C milk
1 C cheese (cheddar or whatever you prefer)
1 tsp dry mustard powder
salt and pepper to taste
optional:
1 C corn flakes (crushed finely)
2 tbsp margarine (melted)

Preheat oven to 350*
Cook macaroni as per directions on the box. Drain and set aside.
While macaroni is cooking, start the cheese sauce.
Melt margarine in a medium sauce pan. Slowly whisk in the flour. A little at a time, begin to add the milk, whisking it in to make the mixture smooth until all the milk is added. Continue to whisk as you bring the sauce to a boil (it will thicken). Mix in the mustard powder, salt and pepper. Grate cheese into the sauce and mix well. Remove from heat.
Spray a large casserole dish with non-stick cooking spray. Add the noodles. Pour the sauce over the noodles and stir in.
Optional: Mix crushed corn flakes with melted margarine and sprinkle over the macaroni.
Bake for 20-30 minutes

-topping alternatives:
1) mix flavoured croutons with margarine to top macaroni
2) grate cheeses over top of the macaroni