Sweet potato cake, oak panna cotta, buttermilk sorbet

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Preparation info

  • Serves 8

    • Difficulty


Appears in

Mile 8: A book about cooking

Mile 8

By David Higgs

Published 2018

  • About
Rust en Vrede

Using vegetables in desserts is not everyone’s cup of tea. I like it as it’s not too sweet and has a lovely savouriness to it.


Sweet potato cake

  • 90 g unsalted butter – to make beurre noisette
  • 90 ml sunflower oil
  • 2 whole eggs
  • 200 g brown sugar
  • 200 g self-raising flour
  • 5 g baking powder
  • 300 g sweet potato – finely grated
  • ½ banana – mashed
  • ½ orange – the zest

Oak panna cotta

  • 3 leaves gelatin
  • ice bath – to hydrate
  • 210 ml full cream milk
  • 210 ml fresh cream
  • 15 ml honey
  • 5 g lemon thyme
  • 10 g smoking wood chips
  • 45 ml brandy


Preheat the oven to 175°C. Line a baking tray with silicon paper. To prepare the beurre noisette for this recipe, place 90 g unsalted butter in a pot over medium heat. Continue to whisk the butter as it melts and begins to foam. Keep the butter on the heat until it begins to brown and the impurities begin to rise to the top. At this point, strain the butter through muslin cloth and set the liquid aside to cool. Once cooled, measure out 50 g of the beurre noisette and combine with the oil.

In a heatproof bowl over simmering water, whisk the eggs and brown sugar until pale in colour and aerated. Whisk in the butter and oil mixture slowly. Sift 180 g of the flour with the baking powder and fold into the butter and sugar mixture, and then mix in the remaining 20 g flour with the finely grated sweet potato. Fold the mashed banana into the cake mixture. Fold in the sweet potato and lastly, the orange zest. Bake in the preheated oven for 30–40 minutes. Once cooled, slice 8 squares, 4 × 4 cm, for serving.

Hydrate the gelatin leaves in the ice bath. Heat the milk, cream, honey, lemon thyme and wood chips in a pot, but do not boil. Once hot, remove from the heat and leave to infuse for 30 minutes, then heat the mixture again and stir in the soaked gelatin leaves and the brandy. Pour through a chinois (fine-meshed conical sieve) to strain the mixture into a bowl and cool over the ice bath (add extra ice to the ice bath used to hydrate the gelatin). Once cooled, pour into 4 cm-diameter round moulds and freeze. When frozen, remove from the mould and store in the fridge.

To assemble, place a square piece of cake on each plate with the panna cotta. Spoon a little pistachio powder onto the plate and position the sorbet on it so that it won’t slide around. Separate the components by placing the sweet potato crisps in between them, and finish with more pistachio powder.