1. Heat oil in a 4- to 6-quart pan over medium-high heat. Add lamb and onion and stir frequently until lamb is crumbly and browned, 5 to 7 minutes.
2. Add rice, grape leaves, parsley, dill, pine nuts, currants, reserved brine, and 4 cups water. Bring to a boil. Reduce heat to maintain a simmer, cover, and cook until rice is tender to bite, 20 to 25 minutes.