Pour the olive oil into a large saucepan set over medium heat, add the diced onion, and cook until softened and translucent, about 5 minutes.

Stir in the rice and cook, stirring, for about 3 minutes, to toast it nicely. Add the wine, season with the salt, and stir constantly until the wine has evaporated, about 5 minutes.

Add half of the broth and the saffron, turn the heat to high, and bring the broth to a simmer, then lower the heat to maintain a steady simmer. Once the broth has evaporated, add the remaining broth and continue stirring until the rice is very creamy; taste a couple grains of rice to be sure it is cooked perfectly—it should be soft but not at all mushy. If the rice is still a bit crunchy, add more water a little at a time and continue to cook and stir for another couple of minutes. When the rice is done, remove it from the heat.

Transfer the rice to a baking dish and let it come to room temperature, then cover and refrigerate. The rice can be reheated on a hot plate as needed on Friday night or at Saturday lunchtime, and it can also be served at room temperature with a spoonful of plain tomato sauce or with pan juices from a roast.