Cut the soft tofu into appropriate sizes.
Finely chop the onion and bell pepper.
Heat olive oil in a pan and sauté the onion and bell pepper.
Add the soft tofu to the sautéed vegetables and season with salt and pepper.
Transfer the soft tofu and vegetables to an oven-safe dish.
Evenly top with tomato sauce and mozzarella cheese.
Bake in a 200°C oven for 10 minutes until the cheese melts.