Peel and dice the onion. Wash and clean the zucchini and aubergine, halve lengthwise and cut into slices. Heat the oil in a frying pan. Fry the minced meat for about 6 minutes while turning it.
After 3 minutes add prepared vegetables. Season to taste with salt and pepper. Mash cheese with a fork and mix with cream and 2 tablespoons of milk. Unroll the puff pastry, cut it into 6 equal rectangles and place them on a baking tray lined with baking paper.
Fold the puff pastry corners towards the middle of the rectangles and fill with minced vegetable mixture. Spread olives on top and add a blob of feta cheese cream to each. Mix the egg yolks and 2 tablespoons of milk.
Coat the edges of the puff pastry with egg milk. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 15 minutes.