Rhubarb & custard crumble cake

Method

• step 1

  Heat the oven to 180C/160C fan/gas 4. Butter and line the base and sides of a 23cm round springform cake tin with baking parchment. Mix a third of the rhubarb with 1 tbsp of the sugar and set aside.

• step 2

  To make the crumble topping, mix the sugar, flour, custard powder and polenta together in a bowl. Add the butter and rub into the dry ingredients until the mixture resembles coarse breadcrumbs, then set aside.

• step 3

  To make the sponge, mix the flour, polenta, custard powder, baking powder and ½ tsp salt in a bowl, then set aside. In a second bowl, beat the butter and remaining sugar until well combined, and lightened in colour slightly. Add the eggs one by one, beating well after each addition. Stir in the vanilla and soured cream, before folding in the flour mix and the remaining rhubarb that was not coated in sugar.

• step 4

  Spread the cake mixture in the prepared tin, then top with the sugar-covered rhubarb and scatter over the crumble topping. Bake for 1 hr-1 hr 10 mins until a skewer inserted into the middle comes out clean. Leave to cool in the tin for 15 mins, then carefully remove from the tin and leave to cool completely on a wire rack. Cut into slices to serve and dust with a little icing sugar, if you like. Will keep in the fridge for up to three days. Pour over double cream to serve, if you like.