Make a marinade using the oil, garlic powder, paprika, black pepper and salt.
Score the top of the pork leg joined in an x pattern.
Rub the pork leg joint with the marinade very well using your hands, wrap it in foil, and let it rest overnight in the fridge.
Take the marinated pork leg joint out of the fridge one hour before roasting, and wait for it to reach room temperature.
Preheat the oven to 180 degrees Celsius.
Roughly chop 2 onions and 5 big garlic cloves and add them to a Pyrex tray.
Add a few springs of thyme, the oil and the oil.
Place the pork leg joint on top, and cover it with kitchen foil.
Bake in the oven for one and a half hours.
Take the pork out of the oven, remove the foil, and pour some of the sauce over it.
Then put it back in the oven uncovered, for another half an hour.
At the end, turn on the grill for 5 minutes, to crisp up the crackling on top.
Take the pork out of the oven and let it rest for 10 minutes, before starting carving it.
Serve with mashed potatoes and pickles.