Serve hot with the mujdei poured into the hole left in the middle or soak them in the mujdei with each bite :)
If you make pirojki with bread dough, it would be good before sprinkling them all with mujdei in a bowl, cover them with a towel and let them soak well for 10-15 minutes. Then serve in the same way, with mujdei next to ....
Good appetite!