- Step 1: Cook the Macaroni: Cook the elbow macaroni according to package directions until al dente. Drain well and set aside. 
- Step 2: Prepare the Roux: In a large saucepan or Dutch oven, melt the butter over medium heat. Whisk in the flour and cook for 2-3 minutes, stirring constantly, to create a smooth roux. This will help thicken the cheese sauce. 
- Step 3: Create the Cheese Sauce: Gradually whisk in the milk, ensuring there are no lumps. Bring to a simmer, stirring constantly, until the sauce begins to thicken. This process typically takes about 5-7 minutes. 
- Step 4: Season the Sauce: Stir in the salt, pepper, and nutmeg. Adjust seasonings to taste. 
- Step 5: Melt the Cheese: Reduce heat to low and gradually add the cheddar, Gruyere, Monterey Jack, and Parmesan cheeses, stirring continuously until the cheese is completely melted and the sauce is smooth and creamy. 
- Step 6: Combine Macaroni and Cheese Sauce: Add the cooked macaroni to the cheese sauce and stir until well coated. 
- Step 7: Prepare for Smoking: Preheat your smoker to 225F (107C). Choose your preferred wood chips for smoking (hickory or applewood are recommended). 
- Step 8: Smoke the Mac and Cheese: Pour the mac and cheese into a greased cast iron skillet or baking dish. Place the skillet or dish in the smoker and smoke for 30-45 minutes, or until the top is golden brown and bubbly, and the mac and cheese is infused with smoky flavor. 
- Step 9: Let it Rest and Serve: Remove from the smoker and let rest for 5-10 minutes before serving. This allows the sauce to thicken slightly.
Optional Tip: For an extra layer of flavor, sprinkle breadcrumbs mixed with melted butter on top before smoking.