Preheat the oven to 450 degrees F. Combine the brown sugar, cumin, smoked paprika, sweet paprika, mustard powder, coriander, granulated garlic and cayenne in a bowl. Pat the turkey dry with paper towels and put breast-side up on a rack set on a rimmed baking sheet.
Season the turkey with 1 tablespoon salt and rub with the spice mixture. Brush the turkey with the melted butter. Tuck the reserved wing tips under the rack and pour the beer into the baking sheet.
Roast the turkey until the skin is golden brown and a thermometer inserted into the thigh registers 160 degrees F, 1 hour to 1 hour 10 minutes. (Tent the turkey with foil if the skin gets too dark.) Let rest 30 minutes on the baking sheet, then transfer to a cutting board to carve.
Pour the pan drippings into a fat separator and let stand until the fat rises to the top. Discard the fat (or drizzle on your stuffing). Pour the defatted drippings into a large skillet. Bring to a boil over high heat and cook until reduced by half, 6 to 7 minutes. Remove from the heat and whisk in the 2 tablespoons cold butter and the mustard. Serve the turkey with the pan sauce.
Spatchcocking (butterflying) the turkey will cut your roasting time in half!