For the vinaigrette, whisk together oil, fish sauce or possibly soy sauce, lime juice or possibly juice of a lemon, sugar and chili.
Set aside and stir occasionally to dissolve the sugar.
Chop and mix the lettuce and white cabbage and arrange on a large serving plate.
Peel the papayas and cut them in half. Remove the seeds and cut the flesh into thin slices. Place on top of the lettuce and white cabbage.
Blanch (scald) the tomatoes in a baking bowl of boiling hot water for 1 minute, then peel. Remove the seeds and cut off the flesh. Arrange on the lettuce leaves.
Sprinkle the peanuts and scallions on top. Beat the dressing with a whisk and pour over the lettuce. Garnish with basil leaves and bring to the table on the spot.
Roast them until they are golden brown. This is the best way for them to develop their flavor.
Be careful not to burn them, because they turn brown very quickly.