I found it! I first saw it in a Morrison's magazine, but I modified it somewhat.. but I've just been through all my magazines and recipes.. I think I need a better way to organise everything; it's taken me hours!
Anyway, the recipe:
Beetroot Chocolate Cake
(Serves 12, apparently..)
225g self-raising flour
79g cocoa
200g demerara sugar
150ml sunflower oil
300g cooked beetroot
3 large eggs
3 tbsp milk
To Decorate:
200g white chocolate, broken up
300g low-fat soft cream cheese
25g grated chocolate / chocolate curls
1. Preheat the oven to 180C/350F/Gas 4. Line the base of a 20cm round cake tin and lightly brush the sides with a little oil.
2. Sift the flour and cocoa into a large mixing bowl and stir in the sugar.
3. In a food processor, blend together the oil, beetroot, eggs, and milk and pour over the dry ingredients. Mix thoroughly
4. Spoon the mixture into the prepared tin and level with the back of a spoon. Bake for 40 mins until a skewer comes out clean when inserted into the centre.
5. To decorate, melt the white chocolate in a bowl over a pan of gently simmering water until smooth. Remove from heat, then beat well with the cream cheese.
6. Spread the mixture over the sides and top of the cake, roughing it up with a palette knife. Scatted grated chocolate / chocolate curls over the top and cut into wedges to serve.
(I use sunflower oil instead of butter to make it lower in saturated fat.)
You can freeze the cake, but only before it's been iced.
Good luck. Let me know how it goes, and don't forget some piccies!