Smoked Cheddar Mac

2 pounds elbow macaroni
1 large onion, diced fine
2 celery stalks, diced fine
1 cup smoked cheddar, grated
1 cup white cheddar, grated
1/4 cup pecorino Romano, grated
5 tablespoons butter (unsalted)
4 tablespoons all-purpose flour
1 quart whole milk
1 cup heavy cream
1/8 teaspoon cayenne
1-2 large gratin/casserole dishes
Butter to grease dishes
Breadcrumbs to top
Salt and pepper to taste

Pre-heat oven to 350°F.
Cook macaroni according to package directions in large pot of SALTED boiling water until al dente. Drain and set aside reserving in the pot it was cooked in. In a saucepan, heat milk and cream over medium heat. Make a roux for Sauce Mornay (cheese sauce) by melting 4 tablespoons of butter in a heavy sauce pan over medium-low heat and adding flour, whisking constantly. Add the warmed milk mixture to the roux slowly, whisking constantly as you pour. Allow the sauce to thicken, until it coats the back of a spoon. Gradually incorporate cheese into sauce, again stirring constantly and being careful to scrape any excess roux from the bottom of pan. Slowly raise heat to medium - medium high, then reduce to low once it thickens, stirring occasionally. Season sauce with salt and pepper to taste. Meanwhile, sauté onion and celery in 1 tablespoon of butter and season with cayenne, salt, and pepper to taste. Combine the onion and celery with the macaroni and cheese sauce. Pour into the greased casserole dishes and sprinkle breadcrumbs on top. Bake at 350°F for 30-40 minutes until the top is browned. Do not over bake. Let set for 10 minutes before serving.