Basil-Marinated Zucchini in the Style of Roman Jews

Concia, marinated zucchini, was a specialty of the Jews in the Roman ghetto. I learned of the dish in Edda Servi Machlins fine book, The Classic Cuisine of the Italian Jews (Giro Press, 1981). The original was deep-fried in prodigious quantities of olive oil. I had the idea to grill the zucchini, which boosts flavor without a lot of fat, reserving the olive oil for the marinade. I also added some grilled onion to hint at the sweetness achieved by deep-frying. Authentic? Not strictly speakin