Black Sesame Sauce

Directions

1. 1
   Toast the sesame seeds in a small saute pan over medium heat, tossing frequently, until the seeds become fragrant and begin to pop.
2. 2
   Transfer them to a plate and let them cool completely.
3. 3
   Grind in 10-second increments in a spice mill or clean coffee grinder to a very fine paste, stirring the mixture, then grinding again, and repeating this process until the paste is completely smooth and glistening from the oil that has been released.
4. 4
   This will take 3 to 5 minutes.
5. 5
   (If the seeds are not ground into a very smooth paste, the sauce will be gray rather than deep black.)
6. 6
   Transfer the paste to a small bowl, add the salt, and gradually whisk in the oil, sake, mirin, and dashi until smooth.
7. 7
   Put 3 cups water and the mushrooms in a nonreactive saucepan and bring to a simmer.
8. 8
   Turn the heat to low, cover, and cook at a very gentle simmer for 10 minutes.
9. 9
   Add the kombu and simmer very gently for 5 minutes.
10. 10
    Remove from the heat and add the bonito flakes.
11. 11
    Let steep, covered, for 8 minutes.
12. 12
    Strain through a fine-mesh sieve.
13. 13
    Discard the solids and use the broth as you would stock.