This is a very popular Slovak dish, which has both sweet and savoury versions. The sweet pirohy made here contain a sweetened cheese filling and are topped with melted butter and fried breadcrumbs.
Put the flour, or flour mixture, into a large bowl. Using a fork, slowly blend the egg and a pinch of salt into the flour, adding cold water to make the dough more pliable, if necessary. On a floured surface, roll the dough out very thinly, then cut into 4cm/1½in squares.
In a separate bowl mix the cheese with the icing sugar and the egg yolk. Spoon the filling