Christmas tree cakes

Method

• step 1

  Heat the oven to 180C/160C fan/gas 4. Oil a 22 x 32cm baking tin and line with baking parchment. Put the cocoa in a heatproof bowl and stir in 125ml hot water from the kettle to make a smooth paste. Leave to cool.

• step 2

  Combine the flour, baking powder, bicarb, brown sugar and ½ tsp salt in a bowl, shaking it a few times to reveal any lumps of sugar, then break these up between your fingers and mix again to fully combine.

• step 3

  Add the oil, yogurt, vanilla and eggs to the cooled cocoa paste, then whisk until smooth. Pour the wet ingredients into the dry and whisk until you have a loose, lump-free batter. Scrape this into the tin and bake in the centre of the oven for 25 mins until a skewer inserted into the middle comes out clean. Leave to cool completely in the tin. Will keep wrapped and frozen for up to three months.

• step 4

  For the buttercream, beat the butter, sugar, vanilla and milk together using an electric whisk until smooth and creamy. Add a few drops of food colouring, then mix again until it’s a bright, even green.

• step 5

  Lift the cooled sponge out of the tin and put on a large board or tray. Turn it so one of the short edges of the sponge faces you. Cut the sides on angle to make a triangular tree shape, then trim the short edge in front of you to make a trunk. Arrange the offcuts on a second board or tray to make another tree, putting the angled pieces together at their longest sides. Use the other offcuts to make the trunk.

• step 6

  Divide the buttercream between two piping bags fitted with star nozzles. To decorate, pipe the buttercream over the trees however you like, leaving the trunks plain, then use sprinkles or sweets for ornaments. Will keep in an airtight container for four days.