Step 1

If one 10-lb. cured smoked bone-in ham or 6-lb. cured smoked boneless ham has a fat cap, score lightly in a crosshatch pattern, spacing cuts about ¾" apart.

Step 2

Transfer ham to a large stockpot and pour in cold water to cover. Cover pot with a lid and bring water to a simmer. Cook, adjusting heat as needed to maintain a simmer, until an instant-read thermometer inserted into the thickest part of ham registers 140°, 70–80 minutes for boneless, 80–90 minutes for bone-in. Remove pot from heat and let ham cool in cooking liquid until lukewarm, about 45 minutes.

Step 3

Place a rack in middle of oven; preheat to 400°. Stir ⅓ cup ketchup, ⅓ cup pure maple syrup, 2 Tbsp. balsamic vinegar, and 2 Tbsp. sriracha in a small bowl to combine.

Step 4

Carefully transfer ham to a wire rack set inside a foil-lined rimmed baking sheet and pat dry with paper towels; discard cooking liquid or save for another use. Brush ham with about half of glaze. Transfer to oven and bake until glaze is tacky and lightly browned in spots, 30–40 minutes. Brush with remaining glaze and continue to bake until glaze is deeply browned, 10–15 minutes more.

Step 5

Transfer ham to a cutting board and let rest 15–20 minutes before slicing and serving.Do ahead: Ham can be simmered 12 hours ahead. Let cool completely, then transfer ham to a wire rack set inside a foil-lined rimmed baking sheet and chill uncovered. Let sit at room temperature 60–90 minutes before glazing and baking.