Prepare pasta according to package directions.

Melt butter in a Dutch oven over low heat. Whisk in flour and cook 1 minute, whisking constantly.

Gradually whisk in milk; cook over medium heat, whisking until mixture thickens and is bubbly. Remove from heat.

Add cheeses, mustard, salt and hot sauce, stirring until cheese melts and sauce is smooth.

Stir in pasta and cook over medium heat, 1 minute or until thoroughly heated. Sprinkle with paprika if desired. Serve immediately.