Finely chop the onion and bell pepper
Preheat the oven to 180°C (356°F)
Add olive oil to a pan and sauté the onion and bell pepper
Add tomato sauce and let it simmer briefly
Place the soft tofu in an oven-safe dish and top with the sautéed vegetables and sauce
Evenly sprinkle mozzarella cheese on top
Bake in the oven at 180°C (356°F) for 10 minutes until the cheese melts