Crumble the feta cheese, blanch the spinach if you have any, whisk together the egg yolks and milk and mix together the oil, crushed garlic clove, chopped onion and the spices.
Place 3 layers of puff pastry on top of each other on the baking paper, brush them with a little oil mixture, then spread the sheep`s cheese (and possibly the spinach) generously on top, cover this with the remaining 3 slices of puff pastry and coat them with the egg yolk mixture.