Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Drain the extra firm tofu and press it between paper towels to remove excess moisture, then cut into 1/2-inch uniform cubes.
Place the tofu cubes, chickpeas, broccoli florets, and sweet potato cubes onto the prepared baking sheet.
Drizzle with olive oil and sprinkle with sea salt, black pepper, and garlic powder, tossing well to ensure every piece is evenly coated.
Spread the ingredients in a single layer and roast for 25 to 30 minutes, tossing halfway through, until the vegetables are tender and the tofu is golden brown.
While roasting, whisk together the lemon juice and Dijon mustard in a small bowl to create a light dressing.
Transfer the roasted vegetables and tofu to a serving bowl, drizzle with the lemon-mustard mixture, and garnish with nutritional yeast and hemp seeds before serving.