Eggplant Mixed Grill

Ingredients

• 2 tablespoons olive oil
• 2 tablespoons chopped fresh parsley
• 2 tablespoons chopped fresh oregano
• 2 tablespoons chopped fresh basil
• 1 tablespoon balsamic vinegar
• 1 teaspoon kosher salt
• 1/2 teaspoon black pepper
• 6 garlic cloves, minced
• 1 red onion
• 18 asparagus spears (about 3/4 pound)
• 12 cremini mushroom caps
• 1 (1-pound) eggplant, cut crosswise into 16 (1/4-inch-thick) slices
• 1 red bell pepper, cut into 6 wedges
• 1 yellow bell pepper, cut into 6 wedges
• Cooking spray