Yarpakh dolmasy (grapevine leaves stuffed with lamb and rice)

3 tablespoons of butter
1 cup of finely chopped onions
1/4 cup of unconverted long-grain, white rice
1/2 pound of ground lean lamb
1 tablespoon of finely chopped fresh coriander (cilantro)
2 tablespoons of finely cut fresh dill leaves
1 tablespoon of finely cut fresh mint
1/4 cup of fresh peas or thoroughly defrosted frozen peas
freshly ground black pepper
28 pickled grapevine leaves
1 cups of chicken stock, fresh or canned
1 pint of unflavored yogurt
1 tablespoon of powdered cinnamon

1. Melt the butter in a 10- to 12-inch skillet set over moderate heat. Add the onions, lower the heat and cook, stirring frequently, for 3 to 5 minutes, or until they are soft and lightly colored. Transfer them to a large bowl.
2. Bring 2 cups of water to a boil in a 1 1/2- to 2-quart saucepan set over high heat. Stir in the rice, lower the heat and cook uncovered for 8 minutes, then drain through a sieve. Stir the rice, lamb, coriander, dill, mint, peas, salt and a few grindings of pepper into the onions and toss all the ingredients together lightly but thoroughly. Taste for seasoning.
3. Bring 4 cups of water to a boil in a 1 1/2- to 2-quart saucepan and drop in the vine leaves. Boil briskly for 3 to 4 minutes, uncovered, then drain and pat the leaves thoroughly dry with paper towels. One at a time, place the leaves rough side up on a flat surface, stem-sides facing you.
4. Heap 2 teaspoons of filling in the center of the leaf and bring up both rounded sides, so that they meet in the middle, thus enclosing the filling. Then beginning at the far side, roll the vine leaf into a loose cylinder, tucking in the ends as you do and allowing enough slack for the rice to expand as it cooks.
5. Arrange the rolls, seam-side down, in a shallow casserole just large enough to hold them in one layer. Pack them in snugly side by side so that they retain their shape while cooking. Pour in the chicken stock and bring to a boil over high heat. Cover the casserole tightly, lower the heat, and simmer undisturbed for about 45 minutes.
6. Serve the vine rolls with a bowl of yogurt sprinkled with cinnamon.