Colourful Blue Buttercream Cakes

For the cupcakes: heat the oven to 180°C (160° fan) 350°F gas 4. Place paper cases in 2 x 12 mini muffin tins.

Beat the butter and sugar until light and creamy. Gradually beat in the eggs until well blended.

Sift in the flour and cocoa and fold in gently with the vanilla and chocolate until just combined.

Spoon into the paper cases and bake for 10-15 minutes until springy to the touch. Place on a wire rack to cool completely.

For the caramel syrup: heat the sugar and half the water in a heavy-based pan. Cook over a medium heat, stirring occasionally, until the sugar dissolves and comes to a boil.

Continue cooking, brushing down the sides of the pan with a wet pastry brush but without stirring, until the mixture becomes golden amber in colour.

Immediately remove from the heat and add the remaining water. Return to the heat and continue stirring until the mixture becomes liquid. Pour into a heatproof container and cool completely before using.

Spoon the caramel syrup over the top of the cakes.

For the topping: whisk together the flour and milk. Heat in a small pan over medium heat. Whisk continuously until it starts to thicken. Continue cooking, whisking all the time until thick. Remove from the heat and leave to cool completely.

Beat the butter and the sugar with an electric whisk until smooth and fluffy. Gradually whisk in the thickened milk mixture and the vanilla. Continue whisking for about 5 minutes until thick and very smooth. Add the food colouring and stir until blended.

Spoon into a piping bag and pipe swirls on the top of the cakes.