Prep smoker to 250 degrees (F)
Trim any excess fat or silver skin. Coat with olive oil and generously coat with dry rub (dry rub is equal parts salt/pepper/garlic powder.
Place on smoker, over indirect heat, until 135 degrees F internal temperature. Roughly 1 hour. Remove and let sit 20 minutes, until cool enough to handle.
Cut into small bite size pieces and reserve 1 1/2 cups for the mac and cheese. Feel free to much on the rest ;)
Prepare noodles according to package instructions, draining them when they are still slightly firm (al dente). Set aside.
In a large saucepan or oven proof skillet (like a large 9" cast iron skillet like you see in the photos) set to medium heat add 1 tablespoon of olive oil (just enough to coat the pan), and add the chopped red bell pepper. Cook until soft (about 5 minutes). Remove the bell pepper from the pan.
Add butter and flour and whisk together for 1-2 minutes.
Add milk, whisk together a and let thicken (about 4 minutes), stirring consistently.
Add the crème fraîche, mix. Next add the nutmeg, Dijon mustard, salt, and the cheese and mix to combine. Once the cheeses have melted add in the cooked bell pepper, and 1 1/2 cups of the smoked tri tip, and the noodles. Transfer to baking dish (or if using cast iron, leave it in there). Top with breading mixture.
Increase grill temperature to 350 degrees prepped for indirect cooking.
Place the skillet directly on the grill, over indirect cooking, and cook 20 minutes. (Alternatively you can cook this in the oven set to 350 degrees as well). Remove and serve.
Note: We intended this recipe to be cooked on a smoker or grill. The instructions and video show a kettle grill, set to indirect cooking, with wood chunks mixed with charcoal.
You can cook the Mac and cheese directly on your smoker or grill, or you can do this part in the oven. Since we use the grill to smoke the tri tip, it's easier to keep using it for the Mac and cheese. But if you want to skip this part and cook it in the oven that's fine. The dish won't take on much more smokiness during this part of the cooking process.