Clean and rinse the spring onions and cut them into very fine slices. Rinse the basil, shake dry and pluck the leaves. Rinse tomatoes, remove stem and cut tomatoes into wedges. Squeeze limes. Cut avocados in half, scrape flesh from skin and mash coarsely with a fork, add lime juice and salt. Spread amount evenly on patties, grind thickly with pepper and spread vegetables evenly on top, roll up tightly and wrap in greaseproof paper.
Tip: Tastes just as great with an additional 400 g North Sea shrimp.