Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Press the extra firm tofu between paper towels to remove excess moisture, then cut into 1-inch cubes.
In a large mixing bowl, combine the tofu cubes, rinsed chickpeas, broccoli florets, and cauliflower florets.
Drizzle the olive oil over the mixture and season with sea salt, black pepper, and garlic powder, tossing well to coat every piece.
Spread the vegetables and tofu in a single layer on the prepared baking sheet and roast for 25-30 minutes, flipping halfway through, until the tofu is golden and the vegetables are tender.
While the bowl base roasts, whisk together the tahini, lemon juice, tamari, and nutritional yeast in a small bowl.
Slowly add 1-2 tablespoons of warm water to the dressing, whisking constantly until it reaches a smooth, pourable consistency.
Transfer the roasted tofu and vegetables to a serving bowl and drizzle the savory tahini dressing over the top before serving.