Preheat the oven to 350ºF and line a rimmed baking sheet with parchment or my preference a silicone baking mat.
Pulse the ham until it's ground down into small bits. This is optional but will create a more combined texture overall and helps keep the loaf in one piece when it's sliced.
Place the butter in a medium-sized skillet set over medium heat and allow it to melt before adding the diced onions. Sauté them until fragrant, about 5 minutes.
Grab a large mixing bowl and move the sauteéd onions to it along with the ham, ground pork, egg, breadcrumbs, milk, all of the spices, and olive oil. Mix the ingredients together (using your hands if needed) until they're all fully incorporated.
Once fully mixed turn the ham and pork mixture out onto the prepared baking sheet and shape it into an 8x4-inch-sized loaf.
Place the baking sheet into the oven to bake for 1 hour or until the center reaches 160º F on a meat thermometer.
In a small bowl whisk the glaze ingredients together and spread it over the loaf with 20 minutes left in the cooking process.
Before slicing the ham loaf left it cool for about 10 minutes.