Roast the pine nuts in a pan without fat while turning them golden yellow. Wash the strawberries, except for some for garnishing, clean and halve them. Cut avocados in half, remove the stone. Peel halves, cut them crosswise into slices and sprinkle with lemon juice.
Clean the salad, wash and drain well. Cut lettuce leaves into bite-sized pieces. Mix vinegar, sherry, a little salt, pepper and sugar, add oil. Season the vinaigrette if necessary.
Turn lettuce leaves loosely in the vinaigrette. Arrange on portion plates with drained avocado slices and strawberry halves. Spoon the vinaigrette over it. Sprinkle with pine nuts and serve garnished with basil and strawberries.