Step 1: Prepare the Brisket: Generously rub the brisket with the dry rub, ensuring all sides are coated. Smoke at 225F (107C) for approximately 2-3 hours, or until the internal temperature reaches 195-205F (90-96C). Rest for at least 30 minutes before shredding or cubing.
Step 2: Cook the Macaroni: Cook the elbow macaroni according to package directions until al dente. Drain well and set aside.
Step 3: Prepare the Cheese Sauce: In a large pot or Dutch oven, melt the butter over medium heat. Whisk in the flour and cook for 1-2 minutes, creating a roux. Gradually whisk in the milk until smooth. Bring to a simmer, stirring constantly, until the sauce thickens.
Step 4: Add Cheese and Seasonings: Reduce heat to low. Stir in the salt, pepper, and nutmeg. Gradually add the cheddar and Gruyere cheese, stirring until melted and smooth. Ensure the cheese is fully incorporated for a creamy consistency.
Step 5: Combine and Bake (Optional): Add the cooked macaroni and shredded brisket to the cheese sauce. Stir until well combined. For a baked version, transfer the mixture to a greased 9x13 inch baking dish. Bake in a preheated oven at 350F (175C) for 20-25 minutes, or until bubbly and lightly browned on top.
Step 6: Serve: Garnish with chopped fresh parsley, if desired. Serve immediately and enjoy the harmonious blend of smoky brisket and creamy cheese.
For a spicier kick, add a pinch of cayenne pepper to the cheese sauce. Smoked Gouda can be substituted for Gruyere for a different flavor profile. For a creamier sauce, consider adding a small amount of cream cheese along with the other cheeses.