- 2 oil-packed anchovy fillets (optional)
- 1small garlic clove, thinly sliced
- 1cup chopped tender herbs (such as parsley, dill, and/or basil)
- 1Tbsp. chopped pickles (capers, cornichons, or chile)
- 2Tbsp. fresh lemon or lime juice or white wine vinegar
- 6Tbsp. (or more) extra-virgin olive oil, dividedKosher salt, freshly ground pepper
- 45–6-oz. skin-on black bass, striped bass, snapper, or salmon fillets
- Flaky sea salt
Using the side of a chef’s knife, mash anchovies (if using) and garlic on a cutting board until a coarse paste forms. Mix in a medium bowl with herbs, pickles, lemon juice, and 5 Tbsp. oil. Season green sauce with kosher salt and pepper.
Swirl remaining 1 Tbsp. oil in a large nonstick skillet to coat. Season fish generously on both sides with salt and lay, skin side down, in cold skillet. Place skillet over medium heat and let it gradually heat up until fat starts to cook out of fish, about 4 minutes. At this point you may press gently on fish so that the skin is flat against the pan. Continue to cook until skin is super-crisp and flesh is mostly opaque (you can increase or decrease heat slightly if needed, but don’t try to rush it), 8–12 minutes longer, depending on the thickness of the fish. Less fatty fish won’t release as much fat on their own, so you may need to add a splash more oil to the skillet if the skin isn’t getting crisp enough. Turn fish and cook just until opaque all the way through, about 1 minute.
Spoon green sauce onto a platter and carefully set fish, skin side up, on top. Sprinkle with sea salt.