Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Press the firm tofu between paper towels to remove excess moisture, then cut into 1/2-inch cubes.
In a large mixing bowl, combine the tofu cubes, chickpeas, broccoli florets, and cauliflower florets.
Drizzle with avocado oil and sprinkle with garlic powder, onion powder, smoked paprika, sea salt, and black pepper, tossing until everything is evenly coated.
Spread the mixture in a single layer on the prepared baking sheet.
Roast for 25-30 minutes, tossing halfway through, until the vegetables are tender and the tofu is golden and slightly crisp.
Remove from the oven and immediately sprinkle with the nutritional yeast and hemp hearts while still hot.
Drizzle with fresh lemon juice before serving in a large bowl.