Preheat oven to 200°C / 392°F.
Lay the potatoes in a pan and place the leg of lamb on top.
Make 4-5 incisions to the meat and insert 2-3 garlic cloves cut in half.
Pour the wine and olive oil in the pan. Cut the remaining garlic cloves in half and toss in the pan here and there.
Season with salt, pepper and oregano.
Add to fingers of water and cover the pan with a piece of parchment paper.
Secure the parchment paper with 1-2 pieces of aluminum foil (so no steam and flavor escapes).
Bake for 1,5 to 2 hours. Prick the meat and if it's tender enough to the point it falls apart, raise temperature to 250°C / 482°F and bake for 10-15 minutes more uncovered until crust gets nice and crispy.