Roll out the dough and cut it into triangles. Melt the butter and brush each triangle. Mix sugar with cinnamon and nutmeg. Sprinkle each triangle with the sugar mixture.

Cut the apple into slices and chop the walnuts into small pieces. Add 1 apple slice and a few chopped walnuts to each triangle and roll up from the wider side. Brush the top with the remaining butter and sprinkle with the remaining sugar mixture. Bake on a tray lined with baking paper at 180°C for 10-12 minutes.