Preheat the oven to 180°C/350°F/gas mark 4. Place 12 paper cases into a regular cupcake tin.
Sift the flour, baking powder and salt into a bowl and set aside. In a small bowl, combine the cocoa powder and food colouring; blend until thick and shiny with no lumps. Cream the butter and sugar together in a large bowl until light and fluffy. Slowly add the egg, then the cocoa paste and vanilla extract; mix until smooth. Add the sifted flour and the sour cream or buttermilk, stirring in alternate spoonfuls until the mixture is well blended.
In a cup, mix the vinegar and baking soda; there will be a fizz! Combine this with the cake mixture. Spoon the cake mixture into the paper cases, dividing it equally, and bake for 20 minutes.
Allow the cakes to cool fully before adding the frosting.
To decorate: Combine the butter and cream cheese; blend until smooth. Sift in the icing sugar and add the vanilla extract. Using a large star-shaped nozzle, ice the cupcakes. Add crowns cut from gold paper using the template on page 136 of the book. If desired, make the crown strip longer, then cut hearts from the crown and add to the crown tips.
Everything Alice by Hannah Read-Baldrey & Christine Leech, published by Quadrille, RRP £14.99