Halve the zucchini or rondini and scoop out with a spoon. Season the vegetables lightly. Chop the hollowed out, place in a bowl and add the olive oil and finely pressed garlic. Finely chop the basil and dice the feta, add both to the filling and season the filling to taste.
Put in the zucchini or rondini and wrap them in aluminum foil, but they should still be a little open at the top.
Cook on the grill, which is not too hot, for approx. 20 minutes.