Step 1

Place the mirin or apple juice in small saucepan and bring to a boil. If using mirin, let it simmer uncovered for about 5 minutes to let the alcohol partially evaporate. Remove from heat, add the miso, and whisk until it is mostly dissolved, although it doesn’t have to be absolutely uniform. Transfer to a blender or food processor.

Step 2

Add the toasted walnuts, and purée until fairly smooth. Transfer to a medium-sized bowl.

Step 3

Stir in the vinegar and garlic. If you are using mirin, add the full 2 tablespoons of vinegar to cut the sweetness a little. Add cayenne to taste. Serve room temperature sauce over freshly-cooked hot food.

Step 5

Note: This dish tastes more intense and slightly sweeter if made with mirin, but it’s very good made either way. You can also make it with half mirin and half apple juice, which is a delicious combination. This keeps for weeks if stored in a covered container in the refrigerator. Reheat very gently before serving.