Preheat oven to 350ºF/180ºC. In a large pot of boiling, salted water cook the pasta 1 minute less than the package recommends.
While the pasta is cooking, in a separate pot, melt the butter over medium heat in a large pan. Whisk in the flour, mustard powder and turmeric, and keep it moving for about 5 minutes to keep from burning. Make sure this is lump free.
In a blender or food processor, puree together the chipotle peppers with 1 cup of milk and then stir into the pan. Stir in the remaining milk, shallots, bay leaf, paprika, and red pepper. Simmer for 10 minutes stirring frequently to keep the bottom from burning. Remove the bay leaf when done.
Place the mixture into a large bowl and temper in the egg; this means scramble the egg, then slowly spoon in small portions of the sauce while stirring to keep it from cooking solid.
Stir in 3/4 of the cheese. Season with salt and pepper to taste. Gently fold the macaroni into the mix and pour into a 2 quart casserole dish. Top with the remaining cheese then bake in the oven for 30 minutes. Remove from oven and let rest for 5 minutes before serving.