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 and set aside.
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, and mix together. 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.