Grease an 8" x 8" baking dish
Cook pasta according to directions on the package, but remove from heat 2 minutes before the directions say, and drain.
Place drained pasta in prepared dish and immediately toss with truffle oil.
Melt butter over medium high heat in a saucepan, then stir in flour, paprika and mustard. Continue stirring until all flour is combined and a thick roux is formed
Whisk in milk, cream and a pinch of salt and bring to a boil.
Simmer, whisking frequently until lumps are smoothed out and sauce thickens, 4-5 minutes.
Remove from heat and add a pinch of pepper. Stir in cheeses, reserving 1/3 of each cheese for topping.
Pour the sauce over the pasta in the baking dish and stir to coat.
Top casserole with reserved cheeses
The casserole can be covered at this point for baking later if desired.
Bring casserole to room temperature before baking at 350 degrees for 30-40 minutes until hot and melted