Cut the soft tofu into bite-sized pieces.
Finely chop the onion, bell pepper, and bacon.
Heat oil in a pan and sauté the bacon, onion, and bell pepper.
Add tomato sauce and bring to a boil.
Add the soft tofu, gently stir, and simmer.
Transfer to a gratin dish and top with mozzarella cheese.
Bake in a preheated oven at 200°C for 10 minutes until done.