Prepare the Marinade: In a large mixing bowl, whisk together the olive oil, balsamic vinegar, fresh oregano, Dijon mustard, fresh rosemary, minced garlic, and coarse salt until well combined.

Marinate the Vegetables: Add the prepared eggplant, zucchini, red onion, and optional green onions to the bowl with the marinade.

Toss gently until every piece is evenly coated.

Cover the bowl and let it marinate in the refrigerator for at least 1 hour, or up to 2 hours for maximum flavor.

Assemble the Kabobs: If using wooden skewers, soak them in water for at least 30 minutes to prevent burning. Carefully thread the marinated vegetables onto eight 10-inch metal or wooden skewers, alternating between the eggplant, zucchini, and red onion. Leave a small ¼-inch space between each piece to ensure even cooking.

Grill to Perfection: Preheat your grill to medium heat. For a charcoal grill, place kabobs directly over the heat. For a gas grill, place kabobs on the rack and close the cover.

Grill for 10 to 12 minutes, turning occasionally, until the vegetables are tender with beautiful char marks.

Serve and Enjoy: Carefully remove the kabobs from the grill and serve immediately over a bed of hot, fluffy couscous.

Cut your vegetables into similar-sized pieces to promote even cooking. This ensures you won't have some pieces that are burnt while others are still raw.

Don't overcrowd the skewers. Leaving a small gap between each vegetable allows heat to circulate, resulting in a better char and more tender results.