Rinse the peppers and chop them finely, removing seeds and stems. Peel the onions, rinse them and chop them. Peel the cucumber leaving a few strips of skin and cut it into thin slices. Rinse the lettuce and spin it. Book it all.
Prepare the sauce:peel the garlic clove and pass it through a garlic press over a salad bowl. Add the lemon juice and zest, sugar, nuoc-mâm and soy. Mix until the sugar has melted.
Grill the beef slices in a non-stick pan for 1.5 minutes on each side and let cool. Then cut them into strips of 3 cm by 5 mm, 3 mm thick.
Put the beef strips in the bowl containing the sauce and mix well.
Divide the heart of lettuce and the cucumber among 4 plates. Add the meat and its sauce. Garnish with onions and peppers, then serve immediately.
You prepare in the same way 200 g of large shelled prawns steamed or just plunged into boiling water and served lukewarm.