Melt 4 tablespoons butter over low heat in a heavy medium saucepan. Add the flour and stir to combine. Cook, stirring constantly, for 3 minutes. Increase the heat to medium and whisk in the half-and-half, little by little. Cook until thickened, 4 to 5 minutes, stirring frequently. Remove from the heat, season with the 3/4 teaspoon salt, white pepper, hot sauce, and 4 ounces Parmigiano-Reggiano. Stir until the cheese is melted and the sauce is smooth. Cover and set aside.
Preheat the oven to 350?F.
Fill a large pot with water and bring to a boil over high heat. Add salt to taste and, while stirring, add the macaroni. Return to a boil, reduce the heat to a low boil, and cook for about 5 minutes, or until the macaroni is al dente (slightly undercooked). Drain in a colander and return the macaroni to the pot. Add 2 tablespoons butter and the garlic and stir to combine. Add the reserved sauce and stir until well combined. Set aside.
Grease a 3-quart baking dish or casserole with the remaining tablespoon of butter and set aside.
In a large bowl, combine 4 ounces Parmigiano-Reggiano with the Cheddar, Fontina, and Gruyere cheeses. Toss to combine. Place one-third of the macaroni in the bottom of the prepared baking dish. Top with one-third of the mixed cheeses. Top with another third of the macaroni and another third of the cheese mixture. Repeat with the remaining macaroni and cheese mixture. In a small bowl combine the bread crumbs, remaining 1/2 ounce Parmigiano-Reggiano, and the Essence and toss to combine. Sprinkle this over the top of the macaroni and cheese. Bake for 40 to 45 minutes, or until the macaroni and cheese is bubbly and hot and the top is golden brown. Remove from the oven and allow to sit for 5 minutes before serving.
Makes 6 to 8 servings