Fry the onion and garlic in some butter or oil. Add the spinach and heat until thawed.

Keep about a tbs of the egg apart and mix it with the milk. Add the rest of the egg to the spinach mixture. Season with salt and a generous milling of pepper.

Roll out each sheet of puff pastry slightly thinner to about 12x12 cm. Put some breadcrumbs on each sheet, leaving a border of about 1 cm. Add a generous scoop of spinach mixture on one half of each sheet (forming a triangle). Top with some crumbled feta cheese.

Brush a little of the milk-egg mixture on the open edges of the triangle and fold over the other half of the dough to seal. Brush the triangles with the remaining eggwash for a nice shine and bake about 25 minutes at 180C

For snack size, use smaller pieces of dough and bake a bit shorter.