Rice pudding cake

This is every bit as wonderful as it sounds: an Italian torta di riso, refracted through the prism of someone who loves a bowl of very British rice pudding. You could make it with pudding rice, but the larger grains of arborio lend it a far better texture.
Makes 8-12 slices
Ingredients
150g arborio rice
700ml full-fat milk
¼ tsp fine sea salt
1 lemon
75g soft, unsalted butter, plus more for greasing tin
3 large eggs, at room temperature
75g caster sugar
2 tsp vanilla extract
nutmeg, for grating
For the sauce (optional):
200g seedless raspberry jam
2 tbsp lemon juice
Method
- Put the rice, milk and salt into a heavy-based saucepan – I use one of 18cm diameter – and finely grate the zest of the lemon into it. Over high heat, and stirring regularly, bring almost to boiling point, but not quite. Turn the heat down to low, and continue to cook for about 30 minutes, stirring every now and then, until the rice is cooked and the milk is absorbed. Keep an eye on it, as you don’t want the milk to start boiling, nor do you want the rice to stick to the bottom of the pan.
- Take the pan off the heat, and stir in the 75g of butter until melted. Scrape the contents of the pan into a bowl large enough to take all the remaining ingredients. Leave for about an hour to cool. Once it’s at room temperature, heat the oven to 160C (140C fan)/320F/gas mark 3, and butter a 20cm springform cake tin.
- Separate the eggs, letting the whites fall into a large grease-free bowl, and drop the yolks into a wide measuring jug (or a bowl). Whisk the whites until stiff, and set aside. Add the sugar to the yolks, and whisk – I use a balloon whisk with vigour, rather than an electric one here – until pale and moussey.
- Add the vanilla extract and two teaspoons of juice from the zested lemon to the yolks and sugar, and then pour gradually into the cooled rice, folding it in well as you go.
- Dollop a large spoonful of the stiffly whisked whites into the rice bowl and stir briskly to lighten the mixture, and then fold in a third of the remaining whites gently but thoroughly, then another third. Once that’s incorporated, fold in the rest. Pour and scrape this mixture gently into the prepared tin.
- Grate nutmeg over generously and bake for 45 minutes; by then the top will have set, with no hint of wobble underneath.
- Sit it on a wire rack for about an hour, until it’s just slightly warm. To ease the unmoulding, slip a small spatula all around the edges, unclip the tin, and transfer the cake, still on its base, to a flat plate.
- Serve each slice drizzled with a little of the sauce.