For my birthday, I wanted to make a nabe (hotpot) and decided to go the extra mile and make dashi from scratch. It isn't very labor intensive and it does taste way better than the dashi granules I very often use, though they taste just fine in a pinch.
I used to know how to make this in my sleep, having learned it from the lovely grandma who manned the kitchen during my childhood homestay in Hokkaido but, since I couldn't remember timings, did a bit of Internet research. I highly recommend the website from which I gathered my inspiration, listed below.
Makes 4 cups, perfect for a hotpot, for a soup base, for drinking on its own but can also be frozen for a couple of weeks.
1 6 x 6 inch piece of kombu (dried kelp)
1 cup of katsuobushi (dried bonito flakes)
4 cups of cold water
Add the piece of kombu to the cold water in a pan and heat very gently over low heat until the water just starts to bubble around the edges.
Remove the piece of kombu and add the bonito flakes. Raise the heat slightly and bring the liquid to a boil.
As soon as it does, turn the heat off under the pan and let the liquid sit for ten minutes before straining the broth. I used a coffee filter to do so and pressed down on the solids remaining behind to get all of the flavor that I could into the broth.
At this point you have four cups of delicious dashi with which to work. I typically stir in four tablespoons each of soy sauce, sake and mirin as well as half a teaspoon of salt before using.
For those of you intrigued by my birthday nabe idea, I decided on Yosenabe (seafood and vegetable hotpot) with thinly sliced cod, shrimp, clams, leeks, shiitake and hon-shimeji mushrooms, Napa cabbage and another Asian green, cubes of tofu and shirataki noodles. I served this with a salad of mixed greens with a carrot-ginger dressing, daikon oroshi (grated daikon with soy sauce), steamed rice and a couple of kinds of Japanese pickle. Everybody cooked their own items in a central pot full of the dashi and had the option of eating each bite with either shichimi togarashi (Japanese mixed pepper), yuzu-kosho, ponzu sauce or hot sesame oil.
Inspiration recipe, here.