1. Preheat oven to 350 degrees. Mince and mash garlic with salt to create a paste. Coarsely grind peppercorns in coffee/spice grinder and stir together with garam masala, nutritional yeast, flour, butter, and garlic paste in a bowl.
2. Spread spice paste over entire ham, then put it cut side down in a greased large roasting pan. Bake in middle of oven until crust is golden and an instant-read thermometer inserted into center registers 150 degrees, about 45 minutes to an hour.
3. Transfer ham to a platter and let stand 15 minutes before slicing.
* Garam masala is a blend of dry-roasted ground spices that is used in Indian, Nepali and other cuisines.