You will need:

• A saucepan and cupcake papers

• Sugar 250g

• Butter 10g

• Water 3 teaspoons

• Vinegar 2 teaspoons

• Food colouring

• String or a seed crystal

Instructions

1. Carefully heat the water & vinegar in the saucepan.

2. Add the food colouring and sugar and stir constantly, slowly dissolving the sugar and bringing to the boil. Allow to simmer for 10 minutes - checking in frequently to avoid burning or overflowing.

3. With an adult, carefully pour the mixture into the cupcake papers and place a string in each of the mixtures.

Why Does This Happen?

Toffee is made from a supersaturated solution of sugar and water. Sugar is dissolved in heated water. When it cools, the sugar crystallises. Seed crystals or a rough string help the crystals nucleate and start to grow – crystals growing from molten rock in a magma chamber work on the same principle.