Simmer the ham hock in the stock over low to medium heat until fork-tender, 1½ to 3 hours. Once tender, remove the hock from the stock and take off all meat from the bone and skin, dice it, and set aside. Reserve the resulting ham hock and stock.
In a stockpot over medium heat, sweat the onions in the lard until translucent, 5 to 8 minutes. Add the pork butt an