Dashi is a basic building block of Japanese cuisine. It is the base for miso and clear broth soups as well as noodle dishes and dipping sauces. It’s the simplest thing in the world to make and imparts your cooking with the mysterious fifth flavor, umami, from the kombu seaweed, and a hauntingly subtle smokiness from the dried bonito tuna flakes.
In fact, that’s all you need to make dashi broth: kombu and bonito flakes, along with water. Stay away from the instant dashi granules available in many Asian supermarkets. They make an incrementally quicker version but the real stuff is far superior and takes minutes to make.
Bring 2 quarts water and 2- 5 x 3-inch pieces of kombu to a boil. Remove from heat and add about a cup of bonito flakes (they often come in little 3-oz. packages. Two packages yields about a cup). Don’t stir. Let sit until the flakes all sink to the bottom (about 5 minutes). Strain the broth through a very fine strainer. You may want to line it with a coffee filter for a very clear broth. Season to taste with a teaspoon or two each of tamari and mirin.
Your broth is ready to use. Use it to simmer vegetables or seafood for a light dinner. Add miso, tofu, and green onions and make miso soup. Simmer noodles and fish together with greens for a quick and healthy dinner. You don’t even need a Japanese cookbook because the authentic flavor is in your broth.