Briefly bake the two naan breads (according to the instructions, but not that long) and let cool down a little.
Pour the sour cream into the bowl. Peel the garlic, chop it into small pieces or press it through a garlic press and add to the sour cream. Mix both with the herbs of Provence and a little lemon juice and season with salt and pepper. Preheat the oven to 200 °.
Peel, halve and slice the onion. Clean the mushrooms and also cut them into slices. Drain the tuna (if possible, the one in oil, as it tastes more intense), remove it from the can and pick it up.
Brush the two naan breads with the sour cream mixture, then cover with the mushroom slices, the tuna pieces and the onions. Sprinkle with grated cheese and bake in the oven for about 20 minutes until the cheese has melted well.