Preheat the grill to the highest setting. You can make the breadcrumbs now or even make them ahead of time.
Slice each zucchini in half lengthwise. Place them on a baking sheet. Scoop out the center using a spoon to create a well. You can discard this zucchini or save it and add it to another dish like pasta, etc.
Sprinkle the zucchini all over with salt and pepper. Spray or brush the zucchini all over with olive oil.
In a bowl, stir together the goat cheese, garlic, basil, lemon zest, pepper flakes and a big pinch of salt and pepper.
Place the zucchini on the grill, cut-side down, and grill for 3 to 5 minutes, until it’s slightly golden and charred. Transfer the zucchini back to the baking sheet. Scoop the goat cheese into the center boat of the zucchini. Once the zucchini are all stuffed, transfer them back to the grill, stuffed side up. Close the lid and grill for another 3 to 5 minutes. The cheese should be bubbly and melty and the zucchini will have grill marks.
Remove the zucchini from the grill and top with the bread crumbs. Top with parmesan if you’d like. Top with fresh basil. Serve!