Cook the elbow macaroni as directed on the package but only for ⅔ of the cooking time listed. My box said 8 minutes so we cooked it for 5 ½ minutes.
Melt the butter over medium heat. Stir in the flour and cook until it begins to turn golden. Add the milks and whisk well.
Cook just until thickened, about 5-7 min on medium.
Remove from the heat and add the seasoning. Add about ¾ of the shredded cheese. Stir in the par-cooked pasta. Transfer to an aluminum foil tray or casserole dish that is grill safe Top with rest of cheese. Cook at 350 for 45 minutes.