Roasted Vegetable and Couscous Salad

INGREDIENTS

• 3 cups broccoli florets, cut into 1/2-inch pieces
• 1 red bell pepper, cut into 1-inch squares
• 1 1/2 cups red onion, peeled and cut into 1/4-inch slices
• 6 tablespoons soybean oil, divided (often labeled "vegetable oil")
• 1/2 tablespoon ground black pepper, divided
• 1/2 teaspoon salt, divided
• 1 1/2 cups dry giant Israeli couscous
• 2 tablespoons balsamic vinegar