1. Place the nuts in a jar of an electric blender and blend at high speed for about 30 seconds. Pour the cream and milk into the jar, and add the cheese, oil, salt and chili paste or fresh chili, and blend again at high speed for about 1 minute, or until the ingredients are reduced to a smooth puree.
2. To make the sauce by hand, crush the nuts with a pestle in a large mortar, then pound in the chili paste or fresh chili and the cheese. When the mixture is as smooth as possible, little by little stir in the oil, cream and milk and season with the salt. Mix together thoroughly and taste for seasoning; the sauce may need more salt.
3. However you have made the sauce, if it seems too thin (it should have the consistency of very thick mayonnaise) thicken it by stirring in finely crumbled soda-cracker crumbs, adding up to ¼ cup if necessary.
4. Now drop the potatoes into a large pan of rapidly boiling, lightly salted water. Boil vigorously, uncovered, until the potatoes can be easily pierced with the point of a small, sharp knife. Be careful not to overcook.
5. Remove the potatoes from the pan with a slotted spoon and drain on paper towels. To serve, center the lettuce leaves on individual plates. Set a potato on each leaf and pour about ¼ cup of the sauce over it. Garnish with hard-cooked eggs and olives. Serve at once.
