Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Press the extra firm tofu with a clean towel to remove excess moisture, then cut into half-inch uniform cubes.
In a large mixing bowl, combine the chickpeas, tofu cubes, broccoli, and cauliflower.
Drizzle with olive oil and sprinkle with garlic powder, sea salt, and black pepper, tossing thoroughly to coat every piece.
Spread the mixture in a single, even layer on the prepared baking sheet to ensure even browning.
Roast for 25 to 30 minutes, tossing halfway through, until the vegetables are tender-crisp and the tofu is golden.
While the bowl base roasts, whisk together the tahini, lemon juice, and nutritional yeast in a small ramekin, adding a teaspoon of warm water if needed to reach a pourable consistency.
Transfer the roasted vegetables and protein to a serving bowl, drizzle with the tahini sauce, and garnish with hemp hearts.