Preheat the oven to 425°F.
Press the tofu to remove excess moisture, then cut it into cubes. In a bowl, toss the tofu cubes with cornstarch, salt, and pepper until evenly coated.
Place the tofu on a parchment-lined baking sheet and drizzle with olive oil. Roast in the oven for 25-30 minutes, flipping halfway, until the tofu is crispy and golden.
Meanwhile, prepare the vegetables: break the broccoli into florets and slice the red bell pepper. Toss them with a light drizzle of olive oil, salt, and pepper, then spread evenly on another baking sheet along with the chickpeas.
Roast the vegetables and chickpeas in the oven for about 20 minutes until tender and slightly crispy.
Cook quinoa as per package instructions if not already prepared.
For the creamy tahini drizzle, simply spoon a tablespoon of tahini into a small bowl. If desired, thin with a little water to reach your preferred consistency.
Assemble the Buddha bowl by layering the quinoa at the base, then topping with roasted tofu, chickpeas, broccoli, and red bell pepper.
Drizzle the tahini sauce over the bowl and serve warm.