In a large pot, saute onions and rice in oil over medium heat until very clear. This will take at least one-half hour. Stir occasionally so it won’t stick. If you see mixture sticks or seems like it’s burning, lower heat.
When onions are limp, add rest of the ingredients – except the grape leaves, of course! Remove from stove and stir until all ingredients are well blended. Cool in pot for about 20 minutes. Tip pot so oil drains from mixture. Set aside for later use.
Fill grape leaves with mixture – about 2 Tbsp., depending on size of leaf. Roll leaves. (See how to prepare fresh grape leaves in Note below.)
Place rolled grape leaves in large pyrex dish, but not more than 3 layers deep. Drizzle the drained oil from pot over the yalanchi.
Add warm water to fill pyrex 3/4 full. Bake, covered, in a preheated 350 degree oven for about 1 hour or until most liquid is absorbed. Check by tasting to see if rice is cooked. If so, remove from oven.