Preheat the oven to 180°C.
Pat the pork leg dry and rub with olive oil, salt, pepper, paprika, garlic powder, herbs, and chopped garlic.
Place the sliced onion in a roasting dish and place the pork on top.
Pour the stock into the dish and cover loosely with foil.
Roast for about 2½ to 3 hours, removing the foil during the last 30 minutes to crisp the outside.
Baste occasionally with the pan juices to keep the meat moist and flavourful.
Remove from the oven and let the meat rest for 10–15 minutes before slicing.