Sauerkraut and mushroom filling

This should correspond to kapusta z grzybami. It if does not, i will need to sort it out one day.

• 2 lb sauerkraut
• 3 oz dried wild mushrooms
• 1 large onion
• 1 hard boiled egg, chopped finely
• Salt, pepper, herbs of choice
• 2 tbsp oil
• Few slices of smoked bacon (or onion, or both)

1. Soak the mushrooms overnight and cook in the same water. Drain, retain the liquid. Chop the cooked mushrooms more or less finely. 
2. Place the sauerkraut in the pot, add the water left from cooking mushrooms, cover, bring to boil and simmer until soft. When soft, take the lid off and let the water evaporate (if not possible, you may need to drain the liquid).
3. Chop the onion finely
4. Heat up the oil in a large frying pan
5. Fry the chopped onion until translucent, add sauerkraut (no water) and mushrooms, spices. Fry for a few minutes, let the flavors blend well
6. Add the egg, mix well.
7. Revise the spices and cool the mix.
8. When the stuffing is cool and the dough is ready, stuff them!
9. Place ready pierogi on flat, floured plates (trays). If they need to wait until boiling, cover them with slightly damp cloth.
10. Boil in the large pot (drop into energetically boiling water, not too many at the time). They will need 3 min since the moment they re-surface.
11. Serve with some hot bacon bits or onion finely chopped and fried in oil..