Thaw the puff pastry slices. Cut the feta into 10 even pieces. Place on the puff pastry slices together with onion rings and season to taste. Moisten the edges of the slices, fold them together and press them down.
Bake in a preheated oven at 200 ° C for approx. 15 minutes until golden brown. Serve hot.
A strong tomato salad with balsamic vinegar, olive oil and onions goes perfectly with it.