There's a very simple way to make a plain baked ham even better: brush it with a sweet citrusy glaze while it's heating, and then whisk together a quick snappy sauce using the pan juices. In this video I'll show you how, from start to finish.
Put a rack in the lower third of the oven and heat the oven to 325°F.
Trim away any skin and external fat on a 7- to 9-lb. half-ham, preferably a bone-in ham. Leave about a 1/4-inch thick layer of external fat. Set the ham fat side up and score the fat 1/4 inch deep with diagonal slices every 2 inches so that it forms a cross-hatched diamond pattern.
Set the ham in a sturdy roasting pan or a baking dish. It should fit fairly snugly with only a couple of inches of space on any side. Add 1-1/2 cups of orange juice to the pan, plus enough water to reach a 1/4-inch depth. Bake for 1-3/4 to 2-1/4 hours, adding water as needed to maintain 1/4 inch of liquid in the pan.
While ham is baking, make the glaze: gently warm 1/4 cup of tangerine or orange marmalade in a small saucepan set over medium-low heat. Stir in 1/4 cup packed light brown sugar, 1/4 tsp. ground ginger, and 1/8 tsp. ground cloves to combine.
The ham is ready to glaze when an instant-read thermometer inserted into the center of the ham registers 105° to 110°F. (it should take about 15 minutes per pound).
Remove the ham from the oven and raise the temperature to 425°F. Add more water to the pan so the liquid is about 1/2 inch deep. Using a large spoon or pastry brush, smear the glaze generously over the top of the ham.
Return the pan to the oven and bake until the glaze on the ham bubbles and begins to darken, about 10 to 15 minutes; the ham should have an internal temperature of 120° to 125°F.
Remove the ham from the oven and transfer to a carving board or large platter. Tent the ham loosely with foil and let it rest for 20 to 30 minutes while you make the pan sauce.
Pour the pan juices into a gravy separator or a 4-cup Pyrex measuring cup. Let sit for 10 to 15 minutes to allow any fat to rise and then pour or spoon off the fat and discard (some hams don't exude much fat).
Pour the pan juices into a 2-qt. saucepan, whisk in another 1/4 cup of marmalade plus 2 Tablespoons freshly squeezed lemon juice. Bring the mixture to a boil. Taste the sauce, and if the flavor isn't as intense as you'd like, continue to boil to concentrate the flavors as desired.
Mix 1 Tablespoon of cornstarch with 3 tablespoons of water. Stir in about half this slurry into the sauce, and whisk until it thickens slightly, about 15 seconds. Add more of the slurry for a thicker sauce. Set aside and keep warm while the ham rests.
Carve the ham, arrange on a platter, and serve with the sauce alongside.