Start by chopping your vegetables. Finely chop the onions; the more finely you chop, the quicker they’ll caramelize. Peel and dice the carrots. Chop the celery into uniform pieces. Set these aside in separate bowls.

In a large pot, heat some oil over medium heat. Add the chopped onions first. Stir them gently, allowing them to sweat and release their moisture. In about 10 minutes, they should become translucent. At this point, add in the minced garlic and ginger for an aromatic base, stirring constantly to prevent burning.

Once the onions are nicely softened and fragrant, it’s time to add the carrots and celery. Stir them in, allowing their flavors to mingle with the onions. Cook for about five minutes. Colors should brighten, and things will start to smell heavenly.

At this stage, you’ll want to pour in the vegetable stock. This is where the soup truly starts to come alive. Bring it to a gentle boil. Be cautious — you don’t want it bubbling away too much.

Once the soup is boiling, add the sliced button mushrooms. They’ll soak up all the goodness in the broth. Next, add your seasonings. Incorporate the rice vinegar, soy sauce, and crushed red pepper flakes. Stir well to combine.

Reduce the heat to low and let the soup simmer for about 20 minutes. This leisurely cooking allows the flavors to develop. Taste it halfway through to see if it needs more salt or pepper. Adjust according to your palate.

Just before serving, sprinkle in the chopped green onions. They add a vibrant color and a fresh crunch that contrasts with the softness of the other veggies. Serve hot in bowls, optionally drizzling some sriracha for a spicy kick.