Ingredients

• ¼ cup raw pistachios
• 10 prunes, pits removed, coarsely chopped
• 1 garlic clove, finely grated
• 2 cups finely chopped parsley
• 1 cup finely chopped mint
• ¼ cup finely chopped tarragon
• ¼ cup kimchi or sauerkraut brine
• 2 Tbsp. Champagne vinegar or white wine vinegar
• Kosher salt
• ¾ cup extra-virgin olive oil
• 1 (2–4-lb.) flatfish (such as sole, flounder, or turbot)
• Extra-virgin olive oil
• Kosher salt
• Aleppo-style pepper

Instructions

1. Toast pistachios in a dry small skillet over medium-low heat, tossing occasionally, until browned in spots, about 5 minutes. Let cool, then finely chop.
2. Gently mix pistachios, prunes, garlic, parsley, mint, tarragon, kimchi brine, and vinegar in a medium bowl to combine; season with salt. Whisk in oil, then taste and season spoon sauce with more salt if needed.
3. Prepare a grill for medium heat. Using a chef’s knife, cleaver, or serrated knife, cut fish crosswise into 2"–4"-wide planks (the larger the fish, the wider the planks); halve planks if fish is large. Pat fish dry, rub all over with oil, and season with salt and Aleppo-style pepper. Grill fish, undisturbed, until about 70 percent cooked through (use a knife to slide into flesh to check), about 5 minutes. The skin should release easily from the grate when the fish is ready to turn. If it’s sticking, keep cooking.
4. Using a large fish spatula, turn fish over and grill until cooked through (fish is done when a paring knife easily pierces the flesh along the side), about 2 minutes.
5. Transfer fish to a platter and spoon sauce over.