Beet and Vanilla Cupcakes with Rose Butter Frosting

method:

• Make the crystallised rose petals the day before you want to serve the cupcakes. They will keep in an airtight container for a few weeks. Lay out a piece of silicon-coated baking paper on a tray. Pick through the petals, choose 12 of the loveliest looking ones and lay them on the tray. Brush the petals gently with egg white, and sprinkle over the caster sugar. Allow to dry in a warm place for eight hours before using.
• When you're ready to make the cupcakes, preheat the oven to 180C/350F/Gas 4. Blend together the sugar and butter until light and creamy, then add the egg yolks, flour, pureed beets and vanilla, and beat until smooth.
• In a clean bowl, whisk the egg whites until fairly stiff. Take a large spoon of egg white and beat into the mixture to loosen it a little. Then, using a big metal spoon, fold the remaining egg whites gently through the mixture, taking care not to over beat.
• Spoon the batter into a cupcake mould (you should have enough mix to fill 12 cases) and bake in the oven for about 20 minutes, or until the cakes are firm to the touch. Remove and cool on a wire rack.
• To make the icing, beat the icing sugar and butter together, either in a food mixer or by hand with a wooden spoon. Add a few drops of rose flower water to taste, and a few drops of beet juice to colour the icing. Spread generously or pipe over the cooled cupcakes and top each with a rose petal.