Step 1: Prepare the Zucchini: Wash and trim the ends of the zucchini. Slice them lengthwise into 1/4 to 1/2 inch thick planks. For less watery zucchini, lay the slices on a baking sheet lined with paper towels, sprinkle lightly with salt, and let them sit for 10-15 minutes. Pat thoroughly dry with fresh paper towels.
Step 2: Make the Marinade: In a large bowl, whisk together the olive oil, fresh lemon juice, minced garlic, finely chopped fresh parsley, thyme, oregano, 1/2 teaspoon salt, and 1/4 teaspoon black pepper.
Step 3: Marinate the Zucchini: Add the prepared zucchini slices to the marinade, tossing gently to ensure every piece is evenly coated. Let them marinate at room temperature for 15-20 minutes, or in the refrigerator for up to an hour.
Step 4: Preheat the Grill: Preheat your grill (gas or charcoal) to medium-high heat (around 400-450°F or 200-230°C). Clean the grates thoroughly.
Step 5: Grill the Zucchini: Arrange the zucchini slices in a single layer on the hot grill grates. Grill for 3-5 minutes per side, or until tender-crisp with clear grill marks. For perfect crosshatch marks, rotate the zucchini 90 degrees halfway through cooking each side.
Step 6: Serve: Transfer the grilled zucchini to a platter. Drizzle with a final squeeze of fresh lemon juice or a sprinkle of flaky sea salt, if desired. Serve immediately and enjoy.