It's much easier to make than you would think. Just go goal set or stretch for a but while it simmers and works its magic.
Heat oil in a large stock pot over medium-high heat. Add the onion, ginger, mushrooms, and garlic to the pot, sauté for 5-8 minutes.
Once the onion becomes translucent, pour 1 cup of broth into the pot to deglaze the pan. Scrape the bottom of the pot with a whisk or wooden spoon to release the flavors
Add the remaining 5-8 cups of broth, tamari (or soy sauce) and stir. Bring the broth to simmer over medium heat then reduce to low and cover. Let the broth simmer for at least an hour, up to 3 hours covered. The longer you simmer the broth the more flavor will be released.
After 1 hour, taste the broth and adjust the seasonings as necessary. Add more tamari, ginger, or a dash of toasted sesame seed oil to add depth to the flavor.
When you are 30 minutes from serving the dish, prepare any desired toppings for your soup such as seared tofu, sliced pork, soft boiled eggs, seared bok choy, roasted broccolini, etc.
Prepare the ramen noodles in a separate pot according to the directions. Rinse throughly before adding to your soup.
Take the broth off the heat and whisk the miso into the broth.
Add your optional toppings and enjoy served warm.