Cut the tofu into bite-sized pieces.
Julienne the onion and bell pepper.
Heat oil in a pan and grill the tofu on both sides.
Place the grilled tofu in an oven-safe baking dish.
Top the tofu with the sliced vegetables and tomato sauce.
Generously add mozzarella cheese on top.
Bake in a 200°C oven for 10 minutes.