Paczki or Polish donuts

This is recipe for traditional Polish donuts, what are very fluffy and delisious. These are prepared from yeast dough, but the preparing method is very different from usual preparing of yeast dough and it also contains special ingredients like spirit. Adding spirit helps to avoid the absorption of excessive oil and helps to form crispy crust.
All this makes from these donuts amazingly fluffy and delicious pastries. 

Recipe I found here:
https://www.kwestiasmaku.com/kuchnia_polska/tlusty_czwartek/paczki_najlepsze/przepis.html

Dough ingredients:
50 g fresh yeast
250 ml milk
3 tbsp sugar
1 tsp salt
500 g flour
1 egg
4 egg yolks
50 g melted butter
1 tsp vanilla sugar
2 tsp spirit

Vegetable oil for frying
Strawberry jam (without pieces- marmalade) for filling of donuts
Powdered sugar fo covering of donuts

Heat milk to 30 C. Mix yeast, 1 tbsp of sugar and 1 tbsp of flour with milk. Cover bowl with food film and put bowl into bigger bowl filled with hot water. Let the yeast activate approximately 15 minutes.

At the same time sieve flour into big bowl and mix it with salt and vanilla sugar. Foam the egg yolks and egg with 2 tbsp of sugar into very strong foam. It will take 15 minutes.

Mix egg foam, yeast mix and flour mix into dough. Knead the dough for 15 minutes. At the end add melted butter and spirit. Knead more until the liquids are combained into even dough. Cover the dough with towel and let it raise for 1-1,5 hour in warm place.

Spread raised dough in flat surface covered with flour. Push air out of dough with your hands. Roll the dough into 2 cm thick layer and cut rings (diameter 6,5 - 7 cm) from the dough. Let rings raise under towel for 30-45 minutes.

At the same time heat the oil in fryer or in pot until 180 C. Bake donuts from both sides approximately 4 minutes until these are golden brown. Let donuts cool a little before starting to filling with jam. If donuts are too warm then the jam will flow out of donuts. For filling use long cake tips (designed specially for pastry filling).

Cover donuts with powdered sugar.