Rinse quinoa in a mesh strainer under cold water to remove its natural coating called saponin. Combine the rinsed quinoa with water or vegetable broth in a saucepan along with a pinch of salt. Bring to a boil, then reduce heat to low, cover, and let simmer for about 15 minutes. Remove from heat and let rest covered before fluffing with a fork.
Preheat your oven to 425°F (220°C). Toss chopped vegetables with olive oil, garlic powder, smoked paprika, salt, and pepper until well-coated. Spread on a baking sheet and roast for about 25–30 minutes, flipping halfway through until golden brown and tender.
In a small bowl, whisk together olive oil, lemon juice, Dijon mustard, maple syrup or honey, minced garlic, and herbs until combined. Adjust seasoning with salt and pepper as needed.
Divide cooked quinoa among four serving bowls. Top each bowl with roasted vegetables and drizzle with dressing.
Add toppings like sliced avocado, toasted pumpkin seeds or pine nuts, and crumbled feta if using. Serve warm or allow to cool slightly before enjoying.