Pour the couscous into the boiling broth, bring to the boil, cover and remove from the heat. Let it steep for 10 minutes, then stir in the butter and let the couscous cool.
Dice tomatoes, cucumber and shallot, pluck the parsley leaves and chop. Mix together oil, vinegar, salt, pepper and garlic. Mix the cooled couscous with everything. Now cut the party prawns into pieces and fold in. Chill the salad and stir it from time to time.
This salad can also be varied to taste with olives and various fresh herbs.