Cut the tofu into bite-sized pieces.
Drain the oil from the canned tuna.
Finely chop the onion.
Heat olive oil in a pan and sauté the onion.
Add the tuna and stir-fry together.
Add the tofu to the pan and lightly stir-fry.
Season with salt and pepper.
Place the stir-fried ingredients in a gratin dish.
Evenly sprinkle pizza cheese on top.
Bake in a preheated oven at 200°C for 10 minutes.