Preheat your oven to 400°F and line a baking sheet with parchment paper.
Press the extra firm tofu for at least 15 minutes to remove excess moisture, then cut into small, uniform cubes.
Toss the tofu cubes in a bowl with the nutritional yeast and a pinch of sea salt until evenly coated.
Spread the tofu on the baking sheet and bake for 20-25 minutes, tossing halfway through, until golden and crisp.
While the tofu bakes, finely dice the yellow onion and sauté it in a non-stick pot with a splash of water over medium heat until translucent.
Rinse the dry red lentils and the canned chickpeas, then add them to the pot along with the vegetable broth.
Bring the stew to a boil, then reduce the heat to low, cover, and simmer for 15 minutes or until the lentils are soft and the liquid has thickened.
Stir in the fresh spinach and cook for 1-2 minutes until just wilted.
Ladle the stew into a bowl and top with the crispy baked tofu cubes before serving.