Cut the soft tofu into bite-sized pieces.
Finely chop the onion, bell pepper, and bacon.
Heat olive oil in a pan and sauté the onion, bell pepper, and bacon.
Add the soft tofu and season with salt and pepper.
Place the soft tofu and sautéed ingredients in a gratin dish.
Top with tomato sauce and mozzarella cheese.
Bake in a preheated oven at 180°C (356°F) for 10–15 minutes.