How to Make It
Preheat oven to 350°F with rack in lowest position. Stir together beer and brown sugar in a large oven-safe high-sided skillet. Add ham; bring to a boil over medium-high. Reduce heat to medium-low; simmer 10 minutes, turning ham occasionally.
Transfer skillet to preheated oven; roast until a thermometer inserted in thickest portion of ham registers 110°F, 1 hour to 1 hour and 30 minutes, turning ham every 20 minutes.
Continue roasting at 350°F, without turning, until a thermometer inserted in thickest portion of ham registers 145°F, 30 minutes to 1 hour, basting ham with beer mixture in skillet every 10 minutes.
Transfer ham to a serving platter; tent with foil to keep warm. Return beer mixture in skillet to heat over medium; cook, stirring often and skimming fat if needed, until thickened, syrupy, and reduced to about 1 cup, about 5 minutes.
Untie ham; brush with 1/4 cup beer glaze. Serve ham hot alongside remaining 3/4 cup glaze.
Irish ham may be ordered online from foodireland.com. If using an 8 1/2-pound spiral-sliced bone-in ham, proceed with step 1 as directed. Tent ham in skillet with aluminum foil; roast at 350°F until the internal temperature registers 110°F, 1 hour and 30 minutes to 2 hours, turning and basting ham every 30 minutes. Remove foil, and place ham on its side in skillet. Proceed with recipe as directed in Steps 3 through 5 (the spiral ham will not be tied, so there is no need to untie it in Step 5).