Cook Maccheroni according to package directions. Drain and chop into small pieces.
Heat 1 Tablespoon butter in a medium saucepan until melted.
Add the flour and stir over medium heat two minutes.
Slowly whisk in the milk or light cream. Heat until slightly thickened. Add the mustard and cheese. Heat until the cheese is melted and the sauce is smooth. Add pasta to the sauce. Add salt and pepper to taste.
Fill cups with Maccheroni and cheese mixture.
To make browned breadcrumbs, melt 1 Tablespoon butter in a small saucepan. Add the breadcrumbs. Stir over medium heat until the breadcrumbs turn a golden brown.
Sprinkle crumbs over pasta. Serve immediately or reheat in 350°F oven.