Cook the elbows following the instructions on the package.

Melt 2 spoons of butter in a casserole or pan at medium heat. Add enough flour to make a roux (a mix of flour and grease used for many basic sauces).

Slowly add the milk to the roux, occasionally stirring. Keep it at low heat until it gets creamy, and then add the cheese and the ketchup.

Pour the elbows in a big casserole or pan, add some bacon and then pour the sauce and start mixing everything.

Melt 2 spoons of butter at medium heat and brown the breadcrumbs. Then, spread it all over the elbows with some more cheese and sprinkle a little paprika on top.

Heat it at 400 °F until the cheese bubbles.