Method
Prep:20min  ›  Cook:20min  ›  Ready in:40min 

1. Whisk together the 250g flour, salt and sugar in a bowl until evenly blended; make a well in the centre of the mixture. Whisk the egg yolk and water together in a small bowl until smooth; pour into the well and mix to form a stiff dough. Transfer the dough to a lightly floured surface and knead until smooth and elastic, about 8 minutes.
2. Roll the pastry with a rolling pin until thin, sprinkling with flour to prevent from sticking. Brush with melted butter and roll it like a swiss roll. Cut with a sharp knife into 4cm slices. Roll each piece into a circle and fill with about 1 tablespoon filling. Fold over into half moons and seal.