Cut bacon into small pieces and sauté for 2 minutes in hot olive oil (until it becomes crispy). Remove with the slotted spoon onto the paper towel.
In the same skillet sauté zucchini slices for 5 minutes, add some oil, if needed. Remove with the slotted spoon onto the paper towel.
In the same skillet sauté onion and garlic until light brown.
Add cherry tomatoes and some oil, if needed; simmer for 2-3 minutes. Remove the skillet from the flame.
Add bacon, zucchini and olives to onion and tomatoes, stir. Distribute the filling evenly on each of the puff pastry sheets, leaving a few centimeters of an empty edge.
Crumble feta cheese over the filling, sprinkle with chopped basil. Fold over the puff pastry edge.
Bake for 20 minutes in the preheated at 220°C or until the edges are light brown and crispy.