1/3 cup peeled and minced ginger root (3- to 5-inch piece)
2 cups chopped scallions (about 1 bunch)
1/2 teaspoon hoisin sauce
1 teaspoon dry rice wine or dry sherry
1 teaspoon sherry vinegar (or rice vinegar)
1 teaspoon usukuchi soy sauce (see note)
3 tablespoons grapeseed or neutral vegetable oil
1/2 teaspoon kosher salt
Place the ginger in the bowl of a small food processor and process for 30 seconds or so. Add the scallions and continue to process for a minute until vegetables form a coarse paste, scraping down the sides as necessary. Don’t process for too long, or the scallions can become bitter. Add the usukuchi, hoisin, sherry, vinegar and salt. Pulse a few times to incorporate the seasonings.
With the motor running, slowly pour the oil in and continue processing until the sauce is emulsified, about 30 seconds.
(If you don’t have a food processor, grate the ginger and mince the scallions as fine as you can. Stir in the rest of the ingredients.)
The sauce can be used right away, but it’s best if it sits for 20 minutes or so. Refrigerate any leftovers.