Wash courgettes and boil them in salted water 3 - 5 minutes, until firm to the bite.
Reserve some from the boiled water. Cut mortadella in 1cm stripes in breadth and quarter salami slices. Peel onion, halve it and cut into rings.
Remove the both ends of crougettes and cut them into thin slices, the big one halve before.
Sausage, onion and parsely mix well with some reserved water. Season to taste with lemon juice, salt and pepper. Marinade for about 20 minutes.