Ingredients

Method

In a medium saucepan, combine 3 cups water, the soy sauce, shiitakes, oyster mushrooms, shallots, garlic, dashima, mirin, balsamic vinegar, rice vinegar, mushroom sauce, and peppercorns. Bring to a boil over medium-high heat. Reduce the heat and simmer for 1 hour.

Discard the vegetables and continue to simmer the sauce until it reduces by half, about 1 hour.

Pour the sauce through a fine-mesh sieve or a cheesecloth and into a container to remove the small bits. Store in the refrigerator for up to 6 months or freeze for future use.