Some people make a fool with yogurt or (Lord help us) instant pudding, but to make a proper fool, you must make custard.
For six servings, scald two cups milk. Cool and add a blend of two well-beaten eggs with a half cup sugar and a teaspoon vanilla. Pour into a double boiler. As it begins to thicken, add a tablespoon of corn starch blended very well in a tablespoon of milk. Once very thick, refrigerate until firm.
To two cups sliced fruit, add a quarter cup sugar and macerate for at least a half hour. Stir if you can think about doing so. Layer fruit and custard, top with stiff cream. Chill and garnish–a dust of nutmeg is a nice touch–before serving.