This is obviously the simplest and cheapest. Dissolve 1 packet of jelly crystals (any flavour) in 1 cup of boiling water. Add 1/4 to 1/2 teaspoon of citric acid. How much depends on how sweet the jelly is to start with and your familys taste. New Zealand jellies are so sweet I normally add the full half teaspoon. Its important that the gelatine be completely dissolved and until my microwave broke down I used it to help or I would have been stirring with a fork for what seems like forever. Impatience caused by lack of time usually has me stirring it over a low flame in a saucepan these days. Cool the jelly and refrigerate until its half set, then beat it until the mixture is thick and creamy.
Make a custard sauce with one cup of milk and 1 rounded tablespoon of custard powder. Leave it to cool with cling wrap covering the surface to stop it forming a skin. Make up a jelly as above and when it and the custard are cool mix them thoroughly together. Leave in refrigerator a few hours to set before serving. Because milk neutralises acid I find I need a little more citric acid in this recipe. Any colour jelly except purple can be used for this recipe.
Whipped Melrose Cream
Make up jelly and custard sauce as for Melrose Cream above. When cool place both in refrigerator until jelly is starting to set. Whip it until thick and creamy, add the custard and whip again. Leave in refrigerator to set for a few hours before serving.