The problem with this recipe is that it assumes that miso paste is just like a bouillon cube, but the two serve completely different functions. A bouillon cube makes a broth, a base for the soup, while miso turns broth into soup. Don't ask me the mechanics of this; I'm no Harold McGee.
So this recipe asked me to boil 2 Cups of water with 1/4 cup of carrot matchsticks and 1/4 Cup of sliced onion for 3 to 5 minutes, then turn off the heat and add cubed tofu and 1 Tablespoon "broth"-dissolved miso paste. And serve. Yeah, right. I may be a student, but I still have standards.
Although my parched innards urged me to cook this faster, I managed to restrain myself. While the water heated up, I tried to make a quick-and-dirty dashi by adding a little bit of rinsed kombu kelp and 1 dried shiitake mushroom. Then when the water boiled I added the carrots and onions and simmered for 5 minutes. I added the 1/4 Cup drained and cubed tofu, turned off the heat, let the soup sit for a minute, and removed the mushroom and kelp. I took some of the hot broth and mixed it with the miso in a little bowl until the miso had dissolved, then I poured the miso sludge into the soup and stirred.
I served this in proper miso soup bowls with chopsticks, hoping for the best, but it turned out As I Feared. The soup tasted pretty bland; without a good broth, it had no depth of flavor. Although the carrots tasted nice, the onion needed to cook more.
Next time what would I do? I would make my usual Miso Soup, even though it takes over an hour instead of 15 minutes (for 8 servings). Or I could try making the broth with bouillon!