Heat oven to 400°F. Trim the ends of zucchini and cut the squash lengthwise into slices about ¼ inch thick. Spread olive oil on the sheet pan and lay out the zucchini slices. Then go back and turn them all over (to coat both sides with oil). Sprinkle with salt. Place peeled garlic cloves around the center of the pan. Bake for 10 minutes. Sprinkle with parmesan cheese and bake 10 to 15 minutes more. Smash the garlic before serving. The browner the zucchini, the better it tastes.