Cut the soft tofu into bite-sized pieces.
Finely chop the onion and bell pepper.
Heat olive oil in a pan and sauté the onion and bell pepper.
Add tomato sauce and bring to a boil.
Place the tofu in an oven-safe dish and pour the sauce over it.
Top with mozzarella cheese.
Bake in a preheated oven at 200°C for 10 minutes.