Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper or a silicone mat.
In a medium saucepan, bring 2 cups of water or vegetable broth to a boil. Add the rinsed quinoa, reduce heat to low, cover, and simmer for 12-15 minutes until the quinoa is tender and the liquid is absorbed. Fluff with a fork and set aside to cool slightly.
While the quinoa cooks, place the sweet potato, bell pepper, zucchini, and red onion on the prepared baking sheet. Drizzle with 2 tablespoons of olive oil, sprinkle with smoked paprika, salt, and black pepper, and toss to coat evenly. Roast in the preheated oven for 20-25 minutes, stirring halfway, until the vegetables are tender and slightly caramelized.
In a small bowl, whisk together the dressing ingredients: 3 tablespoons olive oil, lemon juice, Dijon mustard, and honey. Season with a pinch of salt and pepper to taste.
In a large mixing bowl, combine the cooked quinoa and roasted vegetables. Pour the dressing over the mixture and toss gently to coat. Add the crumbled feta (if using) and chopped parsley, stirring lightly to distribute.
Serve warm or at room temperature as a main dish or side. Enjoy your quinoa salad with roasted vegetables, perfect for a healthy lunch or dinner!