Preheat oven to 350 degrees F.
Line a shallow roasting pan with foil. Place ham on the rack in the roasting pan.
Put an ovenproof meat thermometer in the ham so tip is in center of the thickest part of the meat and does not touch bone.
In a 1-quart saucepan, heat wine, thyme sprigs, and shallot to boiling over medium-high heat.
Reduce heat and simmer uncovered until the wine is reduced to ½ cup.
Remove from heat and discard thyme sprigs. Stir in peach preserves, brown sugar, and mustard.
Brush half of glaze mixture over ham.
Bake ham uncovered 1 hour 30 minutes. Baste ham with remaining glaze mixture every 30 minutes.
Cover ham loosely with foil, and bake for another 30 minutes, or until thermometer reads 140 degrees F.
Remove ham from oven and let stand 15 minutes before serving.
