Ingredients

Step by step

1. Start with the custard cream (or crema pasticcera). Put the milk, vanilla and 15g of the sugar in a pan. Heat over a medium heat until just starting to simmer. Meanwhile, use a balloon whisk to whisk together the egg yolks, cornflour and remaining sugar in a large bowl until combined. Once the milk is just simmering, gradually whisk it into the egg mixture. Return the whole mixture to the pan and cook, whisking constantly, until thick – it will go lumpy at first, then become smooth in about 1-2 minutes. Transfer to a clean bowl, cover the surface with crumpled baking paper and leave to cool for at least 1 hour.
2. For the cake, preheat the oven to 180°C, fan 160°C, gas 4. Grease a 23cm-diameter cake tin and line the base with baking paper. Use an electric hand mixer to beat together the eggs, sugar and lemon zest until pale and thick – about 7-10 minutes. Gradually whisk in the oil, followed by the milk, until combined. Sift over the flour and baking powder, add the salt, then briefly whisk on a low speed until combined and no streaks of flour remain. Spoon into the prepared tin. Beat the custard cream with a balloon whisk until smooth again, then add random dollops on top of the cake batter.
3. Bake for 40-45 minutes, or until the cake is golden and a skewer inserted into the centre comes out clean (avoiding the pockets of custard). Allow to cool in the tin for about 30 minutes, then transfer to a wire rack to cool completely. Dust with icing sugar and slice to serve. Store leftovers in an airtight container in the fridge for up to 4 days.