A key ingredient in several of the Persian dishes served at Kolbeh, saffron is also a crucial component in French bouillabaisse, Spanish paella and Milanese risotto. The stigma of a type of flowering crocus grown mostly in Mediterranean regions, saffron adds subtle nuttiness and slight bitterness to any dish. Home cooks are often afraid to experiment with these bright yellow threads because they're the most expensive spice on the planet -- a gram of saffron costs about three dollars. Fear not, for a little goes a long way. Powdered saffron is easier to use; saffron threads need to be steeped in a hot liquid for at least 20 minutes before they can be added to recipes.
Here's a low-fat one for thyme-scented scalloped potatoes that's been adapted from www.saffroninfo.com, a super-informative online site. Thinly slice 4 large Yukon Gold potatoes and 2 large onions. Mince 2 garlic cloves. In a saucepan over medium heat, wilt the onions and garlic in just enough vegetable stock to keep them from sticking to the pot. When soft, remove from heat and drain off excess liquid. Add 11/4 cups of skim milk to the pot and heat. When the milk has heated, remove from stove, add 1/4 teaspoon of saffron threads and let sit at least 20 minutes. Spray a medium-sized casserole with non-stick cooking spray and cover the bottom of the dish with a layer of sliced potatoes, then a layer of onion-garlic mixture. Lightly sprinkle salt and pepper as well as a pinch of dried thyme over each layer. Layer the remaining potatoes and onions. (Depending on the size of the casserole, this should result in up to four layers.) Pour saffron milk over the top to fill the casserole. Bake covered with aluminum foil in a 350º oven for 45 minutes, or until fork-tender. Remove foil and bake for another 15 minutes, allowing potatoes to brown on top. Serves four.