Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Press the extra firm tofu between paper towels to remove excess moisture, then cut into half-inch cubes.
Rinse and drain the chickpeas, then pat them very dry with a clean kitchen towel to ensure they crisp up in the oven.
In a large mixing bowl, toss the tofu cubes, chickpeas, and broccoli florets with olive oil, garlic powder, sea salt, and black pepper.
Spread the mixture in a single layer on the prepared baking sheet and roast for 25 to 30 minutes, tossing halfway through, until the tofu is golden and the broccoli is tender.
While the vegetables roast, whisk together the tahini, lemon juice, and nutritional yeast in a small bowl, adding a tablespoon of warm water if needed to reach a drizzling consistency.
Transfer the roasted tofu and vegetables to a serving bowl, sprinkle with hemp hearts, and drizzle the creamy lemon-tahini sauce over the top before serving.