Braised Lamb With Preserved Lemon

2 tablespoons olive oil 4 (1 -1 1/4 lb) lamb shanks , patted dry 1 medium onion , finely chopped 1 large lemon , thinly sliced 1 navel orange , thinly sliced[...]

1/4 cup olive oil , divided 2 lamb shanks (2 pounds total) 4 garlic cloves , thinly sliced 2 preserved lemons , thinly sliced 1 cup dry white wine 1 cup low[...]