Step 1: Roast the Vegetables : Preheat oven to 425°F (220°C). Toss zucchini, bell peppers, eggplant, and red onion with olive oil, salt, pepper, and oregano. Spread evenly on a baking sheet and roast for 20–25 minutes, stirring halfway through, until vegetables are tender and lightly caramelized.
Step 2: Prepare the Couscous : In a small saucepan, bring vegetable broth or water and 1 tablespoon olive oil to a boil. Stir in couscous, cover, and remove from heat. Let it steam for 5 minutes. Fluff couscous with a fork.
Step 3: Make the Dressing : In a small bowl, whisk together olive oil, lemon juice, Dijon mustard, minced garlic, salt, and black pepper.
Step 4: Assemble the Salad : In a large mixing bowl, combine couscous, roasted vegetables, olives, and feta. Pour the dressing over the salad and toss gently to combine. Sprinkle with fresh parsley and mint if desired.
Step 5: Serve : Serve warm, at room temperature, or chilled.