Wash the salad and shake dry. Wash the grapes, pluck them from the panicles and cut them in half. Peel and halve onions and cut them into fine strips. Halve the avocado and remove the core. Remove the flesh from the skin with a spoon.
Cut the flesh into cubes and sprinkle with lemon juice. Roast walnuts in a pan without fat until golden brown.
Mix vinegar, honey and mustard together and add oil. Season to taste with salt and pepper. Mix the dressing and the prepared ingredients together and arrange in a bowl.