Ingredients: 

1lb/450g. icing sugar

3 teaspoons. gum tragacanth or gum arabic - warmed (optional)

5 teaspoons water

3 teaspoons powdered gelatine

2 teaspoons white fat (you might see this labelled as dough softener)

2 teaspoons liquid glucose

1 egg white

Method: 
  1. Sprinkle gelatine onto water, leave to 'sponge'.
  2. Using a double boiler, heat the gelatine until it's melted.
  3. Warm the liquid glucose and white fat together, then add the gelatine, egg white, and gum (if used)
  4. Beat in the icing sugar (by hand or electric mixer) until it's stringy.
  5. Grease your hands slightly with a little more white fat, and knead the paste into a ball.
  6. Split mixture into about four sections and seal each into a polythene bag (squeeze out as much air as you can) and then into an airtight container in the fridge.
  7. The paste is best used within 48 hours, but you can keep it up to a fortnight in the fridge, or freeze it for even longer.

When working with it, you'll find that using a little white fat works better than icing sugar to prevent sticking, with the added benefit that it won't leave white marks if you colour the paste. I don't bother to make sugarpaste. I do think that home-made tastes nicer, but this is one situation where I'm willing to trade taste for convenience.