1. Bring a large pot of salted water to a boil and cook pasta until al dente, meaning they still have a bit of chew and texture (not too soft).
2. Preheat your smoker to 225 F and place your favourite wood. Personally I like a mild fruitwood such as peach or cherry.
3. Heat a 12 inch cast iron skillet over medium heat. Melt 1/2 cup of butter and whisk in the flour until a smooth, thin paste forms. Then whisk in the mustard powder.
4. Pour in the milk and bring to a soft boil while whisking. Reduce the heat and whisk in the cream cheese until smooth.
5. Whisk in both cheeses and stir until melted. Take off the heat and pour in the cooked pasta. Stir gently until all the pasta is coated by the sauce.
6. Combine the melted butter, salt and pepper and panko bread crumbs in a small bowl. Sprinkle over the top of the mac and cheese. I like to go heavy with the pepper in this recipe
7. Place the skillet in the smoker, close the lid, and smoke for 1 hour. You can smoke for up to 2 hours if you want a stronger smoker flavor, but the noodles will take on quite a bit of smoke fairly quickly, so I suggest taking it easy, at least for the first time.
8. Serve your mac and cheese while it is still warm and the cheese is nice and melty!