Wash and slice the zucchini into strips about 3/4 centimeter thick.
Use a sharp paring knife to score shallow hash marks on both sides of each slice—this helps the marinade soak into the flesh. All is explained in the video below.
In a mixing bowl, whisk together olive oil, sea salt, black pepper, thyme leaves, crushed garlic, and lemon juice to create the marinade. Add red pepper flakes if you’d like a touch of heat.
Brush both sides of each zucchini slice with the marinade and place them on a sheet pan.
Preheat your grill pan (or outdoor grill) to high heat. Grill the zucchini for about 3 minutes per side until tender and slightly charred. You may also place these under the broiler of your oven for 3 minutes per side.
As they cook, brush with any leftover marinade for extra flavor. I'd also recommend placing them back onto the sheet pan you first marinated them on, as there will be remnants of the marinade there.
Remove from the grill and, if desired, sprinkle with a bit more sea salt and black pepper. Serve warm.
