1 7½ to 8 pound bone-in smoked, cured ham
2¼ cups water, divided
1/2 cup orange marmalade
1/4 cup, plus 2 tablespoons light brown sugar
3 tablespoons fresh lemon juice
2 tablespoons Sriracha
1½ tablespoons grated fresh ginger
Preheat the oven to 350°F. Using a sharp knife, remove the rind from the ham, leaving at least a 1/4-inch thick layer of fat all around. Score the fat in a cross-hatch pattern, at 1/2-inch intervals. Set the ham in a large roasting pan and add 1½ cups of water.
In a blender or food processor, combine the marmalade, brown sugar, lemon juice, Sriracha and ginger. Add 3/4 cup water and puree until smooth. Strain the mixture through a fine meshed sieve into a bowl, pressing hard on the solids to extract as much liquid as possible. Brush the top of the ham with ¼ cup of the glaze. Cover with foil and bake for 1½ hours, until just heated through. Baste with the pan juices occasionally.
Remove the foil and brush with half of the remaining glaze. Bake, basting with the pan juices occasionally, until an instant-read thermometer inserted into the center registers 145°F, about 30 minutes longer. Brush with the remaining glaze and bake until the glaze is caramelized and lightly charred in spots and an instant-read thermometer registers 155°F, about 30 minutes longer.
Carefully transfer the ham to a platter and pour the pan drippings into a bowl. Spoon off the fat from the surface and transfer to a small pitcher. Slice the ham and serve it with the pan drippings.