Directions

1. Preheat a grill pan over medium heat. Season zucchini, squash, eggplant, onion, and red pepper with salt and pepper. Lightly brush vegetables with oil.
2. Place zucchini and squash on grill pan and cook, turning once, 3 minutes per side; transfer to a plate. Place eggplant on grill pan and cook, turning once, until nicely caramelized and tender, about 4 minutes per side; transfer to plate with zucchini and squash. Place onion on grill pan and cook, turning once, 4 minutes per side; transfer to plate with zucchini, squash, and eggplant.
3. Place red pepper on grill and cook until all sides are charred, about 10 minutes. Place the pepper in a bowl and cover with plastic wrap; let steam 10 to 15 minutes. Remove pepper from bowl and peel using a paring knife. Cut pepper in half, remove stem and discard seeds; transfer pepper to plate with zucchini, squash, eggplant, and onion.
4. Cut all vegetables into bite-size pieces; set aside.
5. Bring a large pot filled with water to a boil over high heat. Add salt and return to a boil. Add couscous and cook until al dente, 7 to 8 minutes. Drain and place couscous in a large serving bowl; toss with 2 tablespoons olive oil. Add grilled vegetables, tomatoes, parsley, and basil; set aside.
6. In a medium bowl, whisk together lemon juice, garlic, and sumac powder. Slowly whisk in remaining 1/4 cup oil; season with salt and pepper. Drizzle over couscous salad and gently toss to combine; season with salt and pepper.