Place wild mushrooms in 2 cups of water for 1 hour.
Join together a slightly warmed milk, yeast, sugar and 3 spoons of flour. Mix it all gently and let it grow for 15 minutes. Place the rest of flour and salt in a big bowl. Add the yeast mixture and an egg. Knead the dough for 10 minutes.
Then melt the butter and let it cool down a bit. Add it to the dough and knead it till it’s smooth and doesn’t stick to your fingers anymore. When ready, let the dough grow in a warm place for an hour. Cover it with a cotton towel and make the filling in the meantime.
Cook the buckwheat according to the instruction placed on a package (in general we cook it in slightly salted water for about 20 minutes). Then let it cool down a bit. Cook the wild mushroom for 30 minutes and let them cool down as well. They should get very soft.
In the meantime chop the onion and champignons. Fry them on olive oil till they get soft and gold. Now chop the cooked wild mushrooms and crush the garlic.
Join the buckwheat with chopped wild mushrooms, garlic and fried champignons with onion. Season the filling with salt and pepper.
Preheat the oven to 200°C. Now roll out the dough into a big (0,5cm thick) circle shape. Place the filling on it and close the shape to a nice semicircle. Join the edges well by pressing them with a wooden fork.
Cover the top of the dumpling with a mixed egg. It will make it glossy. Decrease the oven temperature to 180°C. Place the dumpling on a flat baking tray lined with baking paper and bake till it’s golden brown, so for about 45 minutes.
Serve your perfect “kulebiak” with a spoon of beetroot purée or a raw carrot salad.