Preheat oven to 350 degrees and prepare a roasting pan with elevated rack, lightly coating it with cooking spray.
In a medium saucepan, bring riesling, thyme and shallot to a simmer for approximately 10 minutes, or until the mixture starts to reduce.
Remove thyme stalks and stir in peach preserves, brown sugar, stone ground mustard and salt, continue to heat for an additional 4-5 minutes. Mixture should be liquid, but lumpy and sticky.
Brush half of peach glaze over ham, making sure to get into all of the nooks.
Bake for 2 hours, basting with remaining peach glaze every 20-30 minutes.
When top starts to brown and crust, loosely place a piece of aluminum foil over top (approximately 1 hour to 90 minutes into cooking).
Remove and allow to rest for 10 minutes before completing the carving and serving.
Let stand 15 minutes before slicing and serving
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