Preheat your oven to 400ºF and line rimmed baking sheet with parchment paper or a silicone baking mat.
Place the Brussels sprouts, onion, squash, garbanzo beans, and garlic on your prepared baking sheet. Drizzle with the olive oil and season with salt and pepper. Toss to evenly coat. Spread the vegetables out into a single layer.
Roast for 20 minutes. Stir the vegetables for even browning. Roast for 10 to 20 more minutes or until slightly golden in color.
In a small bowl, whisk together the peanut butter, lemon juice, water, and sriracha until smooth.
Divide the quinoa between 2 bowls and top with the roasted vegetables and beans. Top with as much peanut butter sauce as you like, and garnish with the chopped peanuts.