Recipe :
1-Make tomatosauce:
Saute onions and garlic in olive oil, add tomatoes, season and add herbs. Leave to cook over a low heat for 20 minutes, blend in a food processor.
2-Roll out pizza base onto a greased oven tray and drizzle with olive oil. Spread with tomatosauce, then arrange tuna and chopped mushrooms on top. Sprinkle generously with grated cheese.
3-Bake in an oven preheated to 450°F (235°C) for 20 minutes.