Mix all the sauce ingredients in a bowl. Whisk until smooth. Set aside.
1 tablespoon miso paste, 2 tablespoons soy sauce, 1 tablespoon brown sugar, 1 tablespoon oyster sauce, ¼ teaspoon ginger powder, ¼ teaspoon garlic powder, 2 tablespoons cold water, ½ teaspoon cornstarch, dash of white pepper to taste