1. To roast the vegetables: Preheat the oven to 400 degrees F. Place the eggplant, zucchini, yellow squash, red pepper, onion, and garlic on a large baking sheet. Drizzle vegetables with olive oil and gently toss. Season with salt and pepper. Place the pan in the oven and roast for about 30-35 minutes, stirring vegetables occasionally. Remove vegetables from the oven and set aside.