- STEP 1
Soak the gelatine in 80ml cold water for 5 mins. Heat the sugar, glucose and 100ml water gently in a pan until the sugar dissolves. Bring to the boil until it reaches 103C. Remove from the heat. Add the soaked gelatine and stir until smooth. Stir in the condensed milk.
- STEP 2
Put the white chocolate into a bowl. Pour over the warm condensed milk mixture and leave for 5 mins. Stir until smooth. Test the mixture with a sugar thermometer – when it cools to 30C it is ready to use. Stir occasionally as it cools to prevent a skin forming.
- STEP 3
For a perfect finish, the glaze has to flow over the cake and drip off the bottom edge. For this, stand the cake on a plate smaller than its base, balance this on a small bowl, then put on a clingfilm-lined baking sheet.
- STEP 4
Divide the glaze between three bowls to as many as you want. Stir gel food colour into each to make different shades. Pour over the cake, alternating colours so they form flowing patterns and cover the buttercream. Any excess will drip off the base. Leave to set for 25 mins. Transfer to a cake stand to serve.