Take roast out of freezer the night before cooking.
Start your fire and make a nice bed of hot coals. You can also use charcoal (20-24) or a combination of both. It’s good to have a fire burning or other coals ready to add if heat is waning. Some coals put out more heat than others so working with fire and coals takes some practice.
While fire/coals are going, cut onion into thin slices.
Place lard in Dutch oven, thawed or fresh roast, sliced onions, and garlic cloves. Add salt on top. Place lid on.
Place Dutch oven on top of bed of hot coals, evenly dispersed underneath.
Keep checking on roast and coals and add a bit of water if it seems to be drying up. The moisture from the roast and onions should probably be enough but you don't want it dry!
Maintain a slow and steady heat for 1-2 hours or more, making sure the roast is not overcooking. Take out early if you want a juicier and rarer meat.
Take off hot lid carefully and let coals burn out safely.
Scoop out roast and put on a cutting board. Slice the meat with a sharp knife and a fork. The roast may crumble apart or slice beautifully.
Plate with your favourite sides and serve!