Saute onions in oil until limp. Remove from heat. Add rice, salt, olive oil, mint, dill, parsley and juice from 1 and 1/2 lemons. Wash grape leaves thoroughly to remove all brine. Separate leaves carefully. Cut off thick stem and place top side of leaf down. Place 1 tbsp filling on underside of leaf.
Starting at base, fold up and fold in sides, rolling towards point. Arrange in layers in dutch oven. Drizzle with olive oil, weigh down dolmades with a heavy plate. Add chicken broth to reach just above plate.
Bring to boil quickly, lower heat and simmer 45 minutes. Add juice of 1/2 lemon when done or if your like me you can add more lemon juice. Serve cold.