The main ingredient found in miso soup is miso paste, which is a traditional Japanese seasoning made from fermenting soybeans with salt and the fungus Aspergillus oryzae (koji). This fermentation process gives miso paste a rich umami flavor, which is the foundation of the soup. Miso soup typically includes dashi, a broth made from kelp and bonito flakes, along with tofu, seaweed, and sometimes scallions or mushrooms. The combination creates a savory, comforting soup that is a staple in Japanese cuisine, enjoyed for both its flavor and health benefits, as it is rich in probiotics and other nutrients.