Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper for easy cleanup.
Drain the extra firm tofu and press it firmly between paper towels or a clean kitchen towel to remove as much moisture as possible, then cut it into 1-inch cubes.
In a large mixing bowl, combine the tofu cubes, broccoli florets, and cauliflower florets.
Drizzle with olive oil and sprinkle with garlic powder, smoked paprika, sea salt, and black pepper, tossing well to ensure every piece is evenly coated.
Spread the tofu and vegetables in a single layer on the prepared baking sheet and roast for 25 minutes, flipping halfway through, until the tofu is golden and the vegetables are tender.
While the oven does the work, prepare the dressing by whisking together the tahini, lemon juice, and tamari in a small bowl, adding a teaspoon of water at a time until it reaches a smooth, pourable consistency.
Build your bowl by starting with a base of warm cooked quinoa, then top with the roasted tofu, broccoli, cauliflower, and shelled edamame.
Finish the dish by sprinkling hemp seeds over the top and drizzling with the creamy tahini dressing.