Beetroot is a natural dye that gives an amazing pink, and we use it a lot in the bakery. Here it stains the icing instead of the usual synthetic food colour. But, if you want an even brighter pink, cheat and add a little food colour, too. And please, whatever you do, don’t use beetroot in vinegar!
Preheat the oven to 180ºC/fan 170ºC/350ºF/gas mark 4. Lightly oil a 23cm diameter, 7.5cm deep, round tin, using a piece of kitchen towel, then line the base with baking parchment.
In a large bowl, sift together the flour, cocoa and bicarbonate of soda, then stir in the sugar. In a food processor, purée the beetroot, then scrape it into a sieve set over a bowl and push out the juices with the back of a spoon. Set them aside for the icing.
Tip the beetroot pulp back into the food processor, then, with the motor running, add the eggs and vanilla, then slowly pour in the oil. Mix until blended.
Make a well in the centre of the dry ingredients, pour in the beetroot mixture and, with a large spoon, gently fold together. Pour into the tin and bake for 45–50 minutes or until a skewer inserted into the centre comes out clean. If it starts to brown too much before it is fully cooked, cut a round piece of foil the diameter of the cake, make a large hole in the centre and open it up. Place it over the cake to let out steam and protect the edges of the top surface.
Remove the cake from the oven, leave it for 5–10 minutes in the tin, then turn it out on to a wire rack until completely cold.
Icing: abstract expressionist
Transform your cake into a work of art. This cake is inspired by Jackson Pollock. We may not lay a huge sheet on the floor as he did, but we do have a small edible canvas covered in bright beetroot-coloured icing. Using a pastry brush and a piping bag, splatter and flick melted chocolate and icing all over the cake and release the artist in you. Ask the children to help, if you dare...
Turn the cake upside down on to a serving plate, so the flat base becomes the top.
Place the icing sugar in a bowl and gradually add the reserved beetroot juice from the cake recipe. If you would like a more shocking pink, you will need extra help from the food colour: drop a little of it (remembering it is very strong) into the icing sugar and stir until well blended and quite bright pink. Make sure you do not use too much, as the icing needs to remain thick enough to coat the back of a spoon.
Pour it over the cake and allow to dry for at least 1 hour.
Place a small heatproof bowl over a saucepan of gently simmering water, making sure the base of the bowl does not touch the water. Add the white chocolate to the bowl and heat until it melts, stirring only very occasionally. Cool slightly, then spoon into a piping bag. Repeat with the dark chocolate. Snip the very ends of both bags. Dilute a little more pink food colour in a dribble of water, making sure it remains darker than the icing covering the cake.
Now for the fun bit: drizzle and flick both colours of chocolate all over your cake canvas, then shake over the pink colour using the pastry brush or toothbrush. Be as freeform as you like, until you have produced your very own edible masterpiece.