Knead the dough mixture and 1/4 litre of lukewarm water with the dough hooks of the hand mixer to a smooth dough, divide into 4 portions and roll out to 4 bases (18-20 cm Ø). Place the pizza bases on 2 greased baking trays, spread with tomato puree and sprinkle with oregano. Drain the pineapple and cut into large pieces. Peel and quarter the onion and cut into thin slices. Cut ham in half.
Drain tuna and pluck into pieces. Cover 2 plates with ham and pineapple, the rest with tuna, onions and olives. Grate the cheese and spread it on the pizzas. Bake the pizzas one after the other in the preheated oven (electric cooker: 200 °C/ gas: level 3) for about 35 minutes
Preparation time approx. 1 3/4 hours