Set the macaroni on to boil, cooking just to al dente.
Meanwhile, heat butter over medium, then add the ground beef and shallot. Cook the beef through, about 5 minutes, then sprinkle on the flour, mustard, nutmeg, and cayenne. Stir it in to lightly toast and evenly distribute.
Pour in the beer and bring to a simmer. Stir while continuing to cook, to let thicken. This will take about three minutes.
Stir in the milk and let it warm through, almost to the point of scalding, then remove from heat. Stir in the cheese.
Sprinkle on some parsley, maybe a hint of freshly cracked black pepper too, then pour a drink, and enjoy!