Four-Cheese Mac and Cheese

At Slow Bar BQ, Brian Perrone makes macaroni and cheese using only cheddar, but his taste is so intense that customers often assume he uses multiple types of cheese. This inspired Perrone to create this decadent version, which includes cheddar, Munster, Swiss and a touch of cream cheese.
In a large saucepan, heat the oil until golden brown. Add the onion and cook over medium heat until translucent, 5 minutes. Add the garlic and cook until fragrant, 1 minute. Add flour to make a paste. Gradually beat the milk until smooth. Bring to a boil, whisking until the sauce thickens. Reduce the heat to low and simmer, whisking frequently, until the taste of flour disappears, 7 minutes. Add the celery seeds, nutmeg, tabasco and cayenne pepper. Add the cheeses until they are melted. Remove from the heat and season the sauce with salt and pepper.Brush a large, shallow baking dish with butter. In a large pot of boiling salted water, cook the wrapped pasta until almost al dente, about 4 minutes. Drain the pasta and return it to the pan. Add the cheese sauce until smooth. Transfer the mixture to the prepared dish and let it stand for 20 minutes.Meanwhile, preheat the oven to 425 degrees. Bake the pasta in the upper third of the oven for 25 minutes, until it begins to bubble and brown. Turn on the grill and bake the pasta for about 1 minute, until lightly browned and crisp on top. Let the macaroni and cheese stand for 10 minutes before serving.