Put the rice, milk and salt into a heavy-based saucepan — I use one of 18cm / 7 inches diameter — and finely grate the zest of the lemon into it. Over high heat, and stirring regularly, bring to the point where it looks like it's just about to boil, though do not let it actually boil. Turn the heat down to low, and continue to cook the milk and rice 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 / 5 tablespoons of butter until melted. Scrape the contents of the pan into a bowl large enough to take all the remaining ingredients. Leave for about 1 hour to cool. Once it's at room temperature, you can move on, so heat the oven to 160°C/140°C Fan/325°F, and butter a 20cm / 8-inch springform cake tin.Separate the eggs, letting the whites fall into a large grease-free bowl (which could be the bowl of a freestanding mixer) and drop the yolks into a wide measuring jug (or a bowl). Whisk the whites until stiff, and set aside for a moment. Add the sugar to the yolks, and whisk — I use a balloon whisk with vigour, rather than an electric one here — until pale and moussy.Add the vanilla extract and 2 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, and when 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 on a wire rack for about 1 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 (unless, like me, you don't mind risking damage trying to remove it), to a flat plate.Just before you are ready to serve the cake, gently heat the raspberry jam with the lemon juice in a small saucepan, giving it the occasional stir, during which time leave a suitable jug filled with hot water in the sink. When the sauce is hot, fill the warmed jug (obviously, emptied of its water!) with the garnet-glossy sauce.