Peel onion and cut into thin rings. Grate cheese. Cut olives into thick slices. Drain tuna. Wash parsley, shake dry and cut the leaves of 2 stems into small pieces
Heat 1 tablespoon of oil in a pan, sauté the onion in it, remove from the heat. Mix flour and baking powder. Mix eggs, wine and 100 ml oil. Stir in the flour-mix. Carefully stir in tuna, olives, chopped parsley, diced onion and cheese and season with salt and pepper. Pour the dough into a greased, flour-spread box form (approx. 11 x 25 cm). Bake the cake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for 35-45 minutes (stick test)
Remove the cake, let it cool down a little and turn it over. Serve lukewarm or cold and garnish with parsley
Waiting time approx. 30 minutes