Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Drain the tofu and press it between heavy plates or a tofu press for 15 minutes to remove excess water, then slice into 1-inch cubes.
In a large mixing bowl, whisk together the harissa paste, olive oil, lemon juice, minced garlic, nutritional yeast, sea salt, and black pepper until well combined.
Add the tofu cubes, broccoli florets, and sliced red bell pepper to the bowl, tossing gently to ensure every piece is thoroughly coated in the harissa mixture.
Spread the tofu and vegetables in a single, even layer on the prepared baking sheet to ensure even roasting.
Bake for 25 to 30 minutes, tossing the ingredients halfway through, until the tofu is golden and the vegetables are tender with slightly charred edges.