macaroni and cheese

i know i know, who makes macaroni homemade? well i have always loved the homemade stuff {it tastes so much better than kraft} but been too afraid to try it. making a sauce with melted cheddar cheese seemed kind of daunting to me for some reason. we really enjoyed it.

1/2 lb. elbow macaroni cooked
1/2 small onion chopped
2 TBS butter
2 TBS flour
2 c. milk
a couple dashes of cayenne pepper
1/4 tsp pepper
1 tsp salt
2 c. cheese {you're supposed to use 1/2 yellow and 1/2 white cheddar, but i used 1 1/2 c. taco blend b/c it was all i had and 1/2 c. parmesan}
1/2 c. bread crumbs

melt the butter in a large saucepan. add onion and cook 4-5 minutes until onion is soft and translucent. add flour and wisk, cook for a couple minutes to cook flour. add milk in a slow steady stream while stirring make sure there are no lumps. cook until a boil {sauce will be thickened} add 1 1/2 cups of cheese and stir until cheese is melted. toss in cooked pasta. pour into a 9x13 casserole dish. mix remaining 1/2 cup cheese with bread crumbs and sprinkle over pasta. bake at 375 for 30 minutes or until crumb topping is browned and pasta sauce is bubbling.