Fresh orange juice
The acidity of the fresh orange juice helps to balance the mayonnaise and the fish.
Wash the apple, core, and cut into small cubes. Peel the onion and dice. Dice the pickles. Pick the mint leaves and roughly chop.
Put the apple, onion, pickles, and mint in a bowl along with the capers, cottage cheese, mayonnaise, and vinegar. Drain the juice of the tuna well, add to mixter, and carefully stir. Season with salt and pepper and let rest for approx. 10 min.
In the meantime, spread the bread slices with butter and brown in the pan over medium heat.
Divide tuna mixture and lettuce leaves between sandwiches. Enjoy!