Use a pestle and mortar to bash the garlic cloves with the sea salt and black pepper until a coarse paste
Add the sweet paprika, dried herbs, olive oil and tbsp of white wine
Mix to make a paste
Slash the top of the leg with a sharp knife, then massage the paste onto the leg and leave to marinate for at least 6 hours or overnight
Take the leg (or shoulder) of lamb, out of the fridge 30 minutes before cooking
Quarter the onions and place in a roasting tray
Place the leg on top and add the cup of white wine into the tray
Cover with foil and roast for 2 and a half hours at 150C
After 2 hours, add baby potatoes, give it a good mix, and add more wine if it needs some liquid
Increase the temperature to 160 degrees C and roast for another hour, covered with foil
After that, remove the foil and increase the temperature to 200 degrees C, baste the leg with the juices and roast uncovered for 20 minutes or so to get some colour. Keep a watch so it does not burn.
The meat should come off the bone easily by this stage
Rest for 15 minutes and serve