Heat the oven to 180C/160C fan/gas 4. Use a little of the vegan spread to butter the base and sides of a deep 23cm cake tin, then line with baking parchment.

Put the plant milk in a jug and mix in the zest and juice of one orange and the cider vinegar. Leave to thicken slightly for 5 mins.

Beat 150g of the vegan spread with the caster sugar using an electric whisk for 1 min until creamy, then add the milk mixture, vanilla extract and a small pinch of salt. Sieve in the flour, baking powder and cocoa. Beat again until combined, and scrape into the prepared tin. Bake for 35 mins – 40 mins until risen and firm to the touch, and a skewer inserted into the middle of the cake comes out clean. Leave the cake to cool for 10 mins in the tin, then turn out on a wire rack to cool completely.

To make the icing, melt the chocolate in short bursts in the microwave, stirring well between each burst, or in a heatproof bowl set over a pan of simmering water (ensuring the bowl doesn't touch the water), until smooth. Leave to cool for 5 mins. Whisk the remaining vegan spread (just under 100g) with the icing sugar and zest of the remaining orange for a few mins until creamy, then mix in the cooled chocolate until smooth.

Put the cooled chocolate cake on a cake stand or plate, and smooth the frosting over the top, spreading it to the sides. Will keep for up to three days in an airtight cake tin. Decorate with more orange zest and chocolate shavings, if you like.