Mirin: An essential Japanese ingredient. It's similar to sake, a rice wine, but sweeter and much lower in alcohol. The sweetness balances out the saltiness of the soy sauce. If all you can find is rice vinegar, add some sugar to it to counterbalance the acidity. To substitute wine, use a wine such as a dry sherry or sweet marsala, adding 1/4 teaspoon sugar to 1/4 cup wine.
Shiitake mushrooms: Dried mushrooms, usually sold in big bags, are easy to store in the pantry and rehydrate before adding them to a stir-fry, a soup, or anything that could use a little umami flavor. If all you can find are fresh shiitake mushrooms, buy about 3/4 pound fresh for every 2 ounces of dried mushrooms you need.
Soba noodles: Chuka soba (curly ramen noodles), soba, or any egg noodle you can find at an Asian market all work. Dried or fresh types all work well but rehydrate them separately according to package directions before using them in the recipe.
Chilies: Add sliced fresh jalapeño peppers and even a tiny, fiery Thai birdseye chili, if you like it spicy.
Yield: One batch of the recipe makes 4 servings of ramen.
Make ahead: You can definitely get the broth made a few days before you need it, and the chicken is easy to poach a day or so beforehand, too.
Storage: Store the broth and various toppings in separate containers in the refrigerator and then assemble the bowl when it's time to eat.
Freezing: Freeze the broth as you would any other stock and you'll always have the umami-rich foundation for ramen at home. Unfortunately, cooked noodles and fresh toppings won't freeze well.
Thicken the broth: If you prefer a thicker soup, whisk in a mixture of cornstarch combined with cold water and allow to simmer for a few minutes. Add more as needed until it is the desired consistency. The amount of cornstarch and water will vary according to how much broth is being used. Start with mixing 1 tablespoon cornstarch with enough water to make a slurry (like a watery paste), then add it a little at a time (not all at once!) allowing the liquid to simmer a minute or two so you can judge the thickness. Add more if you want to, but only in small amounts.
Toppings: In traditional ramen, toppings are a very important part of the dish. Fun toppings such as braised pork belly, toasted sesame seeds, bean sprouts, and baby corn are common, as well as spinach and bok choy.