Process vegetables, scraping down sides of food processor bowl as needed, into a coarse paste, about 30 seconds. Stop processor and add parsley, celery leaves, fennel fronds, and scallion greens to food processor bowl. Continue processing until herbs are broken down and well-combined with vegetable mixture, about 30 seconds. With food processor still running, gradually add remaining 4 tablespoons butter, making sure butter is emulsified into paste before adding more. Stop processor and add panko bread crumbs. Pulse mixture until bread crumbs are fully incorporated. Season to taste with salt, erring on the side of less salt, since the oysters are briny. Transfer mixture to disposable pastry bag or small mixing bowl, and set aside. If using a mixing bowl, cover with plastic wrap, pressing plastic against surface of the paste to prevent skin from forming. If not serving immediately, mixture can be stored in refrigerator for up to 1 day; let sit at room temperature to soften before using, about 30 minutes.
Published at Wed, 09 Jan 2019 10:28:27 +0000