In a 3 quart saucepan, heat the olive oil over medium heat. Add the onion and garlic and cook until soft and light golden brown, 8 to 10 minutes. Add the thyme and carrot and cook until the carrot is quite soft, about 5 minutes.
Add the tomatoes, with their juice, and bring to a boil, stirring often. Lower the heat and simmer until as thick as hot cereal, about 30 minutes. Season with salt. The sauce can be refrigerated for up to 1 week or frozen for 6 months.
Mix the parsley, pine nuts, and lemon zest loosely in a small bowl. Set aside until ready to serve. Makes ½ cup
In a 12- to 14-inch skillet, heat the olive oil over medium heat. Add the onion and cook until softened and translucent but not browned, 8 to 10 minutes. Add the saffron and cook, stirring, for 1 minute. Add the rice and stir with a wooden spoon until toasted and opaque, 3 to 4 minutes.
Add a 4- to 6-ounce ladle of the stock and cook, stirring, until it is absorbed. Continue adding stock a ladle at a time, waiting until the liquid is absorbed before adding more. Cook until the rice is tender and creamy and yet still a little al dente, about 15 minutes. Stir in the butter and cheese until well mixed.