Here is what you need for this:
8 oz. elbow macaroni
1 lb. pork sausage
1/2 cup chopped onion
1/2 cup chopped green or red bell pepper
4 Tbs. flour
1/2 tsp. salt
1/4 tsp. black pepper
3 cups milk
3 cups shredded cheddar cheese, divided ( use what you like, sharp, mild...doesn't matter)
Cook the macaroni according to the package directions minus about a 1 minute of cooking time. Be sure to salt the water. Drain and set aside.
Add the milk and cook until it starts to bubble and thicken a little. Let it bubble for a minute or two. When it's thickened a little, turn the heat down and add 2 cups of the cheese. Save the other cup for the top.
Pour into a 2.5 or 3 quart casserole dish that has been sprayed with nonstick spray. Sprinkle the other cup of cheese over the top.
Place in a 400 degree oven for about 25 minutes or until golden brown.