For the ham: Preheat the oven to 325 degrees F and adjust the oven rack to the lowest level.
Using a sharp paring knife or box cutter, score the entire fat layer of the ham with deep cuts (being careful to not cut into the meat) in a 1/2-inch-wide diamond pattern.
Place the ham cut side-down in a roasting pan fitted with a rack and add water to the bottom of the roasting pan about 1/2 inch deep. Cover loosely with foil and bake for 45 minutes.
Meanwhile, make the glaze: In a small saucepan over medium heat, stir together the honey, jam, mustard, vinegar, garlic, jalapeno, orange zest and juice and pepper to taste until combined. Bring to a gentle simmer over medium heat. Cook, stirring often, until the glaze is slightly thickened, 3 to 5 minutes. Remove from the heat and set aside.
Remove the foil from the ham and spoon the pan drippings over the top; then generously brush the glaze all over. Continue baking the ham, uncovered, and repeat the basting with juices and brushing with glaze every 20 minutes until the glaze is deep golden brown and caramelized or until the internal temperature reaches 130 degrees F, 10 to 12 minutes per pound, about 1 hour more.
Loosely cover the ham with foil and let rest 15 minutes before slicing. Serve warm or at room temperature as a main course, or prepare a sandwich bar.
For the ham sandwich bar: Arrange all the ingredients on the table or counter. I like to assemble my sandwich like this: Put cheese and then a couple of slices of ham on a bun bottom. On the bun top, dollop mustard and mayo, then top with cornichons and Pickled Red Onions. Close up the sandwich.
Pickled Red Onions:
Yield:1 1/2 cups
To a saucepan, add the vinegar, sugar, salt, bay leaf, red pepper flakes to taste and 1/2 cup water and bring to a boil. Put the onions in a heatproof container and pour the boiling pickling liquid over them. Let the onions sit for 30 minutes to let cool. Cover and refrigerate until ready to use.