Soak the rolls in cold water for about 10 minutes. Peel and finely dice the onion. Wash parsley, dab dry, remove leaves and chop finely, except for a few for garnishing.
Squeeze the bread roll, knead with minced meat, onion, parsley and eggs to a smooth mixture. Season with salt and pepper. Form approx. 9 flat meatballs from the minced mass with wet hands. Heat oil in a pan and fry the meatballs for about 10 minutes, turning them over at medium heat.
In the meantime, wash and clean the tomato and spring onions. Wash, clean and quarter the mushrooms. Cut spring onions into rings of about 1 cm thickness. Cut tomatoes into 3 slices of about 1 cm thick. Take out the meatballs.
Gouda, camembert and mozzarella in thirds. Cut the pineapple into pieces. Cover 3 meatballs each with mushrooms, spring onions and Gouda. Cover 3 meatballs with pineapple and camembert. Cover the remaining meatballs with tomatoes and mozzarella.
Place them all on a baking tray and bake in the preheated oven (electric: 225 ° C/ gas: level 4) for about 5 minutes. Cut the olives into slices. Sprinkle the pineapple-camembert meatballs with fried onions and the tomato-mozzarella meatballs with olives.
Arrange everything on one plate. Garnish as desired with tomato wedges and the remaining parsley.