Orange, polenta and olive oil cake with mascarpone and thyme

Method

1. Heat the oven to 170°C/150°C fan/ gas 3½. Put 2 of the oranges in a large saucepan and pour over cold water to cover. Bring to a simmer and cook for 1 hour 15 minutes until soft when pierced with a sharp knife. Cut out the green stalks, then whizz in a food processor to a smooth purée. Set aside. Line the base of a 23cm loose- bottomed cake tin with baking paper, then oil well. Sprinkle 10g of the 290g caster sugar over the base of the tin. Remove the peel and white pith from the remaining oranges with a paring knife, then slice them into even rings, removing any seeds. Collect any juice that runs out in a small bowl and mix in the 50g sugar (for the caramel).
2. Layer the orange slices, overlapping, in the tin on top of the sugar to cover the base completely. Mix together the polenta, baking powder, almonds and remaining 280g sugar in a bowl, then whisk in the eggs, one at a time, followed by the 220ml olive oil and the orange purée. Once the mixture is smooth, carefully pour it over the oranges, trying not to dislodge the pattern.
3. Bake for 1 hour 20 minutes or until a skewer pushed into the centre comes out clean. Cool for at least an hour before turning out.
4. Whisk the mascarpone with the icing sugar in a bowl, add half the picked thyme leaves and set aside. Pour the orange juice and sugar mixture with a splash of water into a small non-stick frying pan and cook over a medium-high heat for 3-5 minutes, without stirring, until a golden caramel forms. Cool slightly, then brush it over the orange slices.
5. Scatter the remaining thyme over the cake and serve in slices with the mascarpone on the side.