Preheat the oven to 350 F and butter a 9 x 13-inch casserole dish. Cook macaroni until al dente. Just slightly undercooked. Drain and return to the pot. Add the melted butter, half and half, salt, ground mustard, paprika, parsley, pepper, cubed Velveeta, and half of the shredded cheeses. Mix everything until well blended.

Pour this mixture into the prepared baking dish and sprinkle what is left of the shredded cheeses on top. Bake for 30 minutes or until the cheese is melted.