You can use any kind of minced meat, vegetables or mushrooms to fill the pelmeni. They can also be frozen so it might be a good idea to make a huge batch because once you get started it doesn't matter if you make 20 or 200. ;) Remember to freeze the pelmeni before boiling them! If you're not sure if you've added enough salt and pepper into the filling, it might be a good idea to cook some of it in the (microwave) oven to check the spices. You need quite a lot of them, esp. if you're not using a meat that has a strong taste.
Recipe posted by Kukka