4-Cheese Mac 'N' Bacon - cooking recipe

Ingredients

butter, for casserole dish
6 -8 slices thick center-cut bacon
1 medium white onion, finely chopped
1/2 cup all-purpose flour
5 1/2 cups whole milk (do not use skim)
2 teaspoons kosher salt
1/4 teaspoon fresh ground black pepper
1/4 teaspoon cayenne pepper
1 1/2 cups grated parmesan cheese (about 4 1/2 ounces)
1 1/2 cups grated gruyere cheese (about 6 ounces)
1 1/2 cups grated Fontina cheese (about 6 ounces)
1 1/2 cups gorgonzola, broken into small pieces (about 6 ounces)
1 lb elbow macaroni

Preparation

Heat oven at 375 degrees. Butter a 3-quart casserole dish. Fry bacon slices; set on paper towels. Pour off all but approximately 3 tablespoons of the bacon grease. Put pan back on medium heat and add onion. Cook about 5 minutes, until softened. While stirring constantly, add about a third of the flour; continue stirring and slowly adding flour, for at least 1 minute.
Transfer onion/flour mixture to a large, heavy saucepan on medium heat. While whisking, slowly pour in milk. Cook while whisking until mixture bubbles and gets thicker (not necessarily \"thick\"). Remove pan from heat. Add salt, pepper, cayenne pepper, the cheeses and stir. Crumble bacon and add it, stirring. Set aside.
Cook pasta in a large saucepan about 2-3 minutes less than box's instructions. Drain pasta in a colander, rinse with cold water, and drain again. Stir pasta into the cooked cheese sauce. Bake until browned on top, about 30 minutes. Let dish stand for at least 5 minutes before serving.