Prepare the 2 bunches collard greens stems removed: Rinse each leaf thoroughly under cold water. Fold each leaf in half lengthwise and strip or cut away the tough center stem. Stack the leaves and slice them into roughly 1-inch strips. Set aside.

In a large pot, heat the 1 tbsp olive oil over medium heat. Add the diced yellow onion diced and cook, stirring occasionally, until softened and translucent, about 5 minutes.

Add the 5 cloves garlic minced (and 1 tsp red pepper flakes if using) to the pot and cook for 1 minute, stirring constantly, until fragrant.

Pull the ham from the refrigerator 30–45 minutes before baking so it heats evenly. Set it on a rack in a shallow roasting pan. Score the surface in a diamond pattern, about 1/4 inch deep, so the glaze penetrates the meat. Insert an oven-safe meat thermometer into the thickest part — keep the tip clear of bone and fat pockets to get an accurate read. Measure your glaze ingredients and have them ready before the ham goes in.

Preheat oven to 325°F. Place rack-mounted ham in oven and bake covered. Timing: 16–20 min/lb for a 7–10 lb bone-in ham; 15–18 min/lb for 10–14 lb; about 1.5–2 hours for 5–7 lb. While it bakes, whisk together a glaze of brown sugar, mustard, and a splash of vinegar or citrus juice. At the 30–45 minute mark before the estimated finish, remove the ham, brush glaze generously over the scored surface, and return it to the oven uncovered. Reapply every 15–20 minutes if you want a deeper crust. Watch closely — sugar glazes burn fast. Done when an instant-read thermometer reads 140°F–145°F in the thickest part. Check early; you can always add time.

Add the 2 bunches collard greens stems removed to the pot in large handfuls, using tongs to press them down and stir them in as they wilt. They will look like a lot at first — keep adding and stirring until all the greens are in the pot.

Taste and adjust seasoning — add more 1 tsp kosher salt, ½ tsp black pepper freshly ground, or a splash more 2 tbsp apple cider vinegar as needed. Serve hot with cornbread for soaking up the pot likker.

Taste and adjust seasoning — add more kosher salt, black pepper, or a splash more apple cider vinegar as needed. Serve hot with cornbread for soaking up the pot likker.