Grilled fish sandwiches with salsa verde are a delicious mess

Many of the most joyful times I have spent with my dad have been by the ocean — flying kites on the beach; digging for clams and cooking them for dinner; eating fish sandwiches at the bar of a ramshackle restaurant on the docks; and making s’mores over a bonfire in the sand at night.

To this day, spending time at the shore with him is my choice activity, and this sandwich reflects the best parts of that, bringing the flavors of the sea and the grill together in a way that is fun, carefree, and just the right amount of messy.

The sandwich’s flavor is driven by a mouthwatering, Spanish-style salsa verde — a puree of fresh parsley spiked with garlic, lemon, anchovies, and crushed red pepper flakes — made luscious with olive oil. If you wind up with any of the salsa left over, you won’t be sorry — it is incredible tossed with cooked shrimp or white beans, spooned over eggs, or spread on crusty bread.

In this sandwich, the salsa verde is smeared generously onto the bottom of a toasted bun. A juicy fillet of grilled white fish — seasoned with just salt and pepper — goes on top of that. (Any firm fish will work, so use whatever looks best at the market.) More of the salsa is dolloped on top of the fillet, followed by a mound of grilled onions and fresh lettuce.

The sandwich delivers an exhilarating experience: The savory salsa elevates the succulent flame-cooked fish to new heights, bolstered by the sweet smokiness of the charred onions and crisp bite of lettuce.

The ample juices and sauce escaping the sandwich as you eat it only add to its pleasure. It is a satisfying sandwich that’s just right for this Father’s Day, ideally at the beach, in a park or a backyard, with plenty of napkins on hand.

4 servings (makes 4 sandwiches)

Total time: 30 mins

The flavor of these grilled fish sandwiches is driven by a bright and herbaceous Spanish-style parsley salsa verde. Generously added to the sandwiches, the sauce gets its punchy flavor from garlic, lemon, anchovies, and crushed red pepper flakes. The ample juices and salsa are bound to escape the sandwiches as you eat, so be sure to have napkins on hand.

You’ll probably have a little leftover salsa verde. It’s great to spread on a sandwich; to drizzle on avocado toast, grilled or sauteed vegetables; or to toss with white beans, cooked shrimp, chicken, and/or potatoes.

Storage: Refrigerate the leftover fish for up to 2 days and the salsa verde for up to 4 days.

Ingredients

For the salsa verde:

2 cups packed flat-leaf parsley leaves and tender stems (from 1 medium bunch)

1/4 cup extra-virgin olive oil

2 oil-packed anchovies, coarsely chopped

1 garlic clove, minced or finely grated

1 tablespoon water

1/2 teaspoon finely grated lemon zest (from 1/2 lemon)

1 tablespoon fresh lemon juice (from the same 1/2 lemon)

1/8 teaspoon fine salt

1/8 teaspoon crushed red pepper flakes, plus more to taste

For the sandwiches:

1 tablespoon neutral oil, such as olive, avocado, or canola, plus more for the grill/pan (see Notes)

1 medium red onion (8 ounces), peeled and cut into 1/4-inch-thick rounds

4 (4- to 5-ounce) firm white fish fillets, such as halibut, mahi mahi, grouper, or tilapia, patted dry

1/4 teaspoon fine salt

1/4 teaspoon freshly ground black pepper

4 hamburger buns

4 leaves red or green leaf lettuce

Steps

Make the salsa verde: In a food processor, combine the parsley, oil, anchovies, garlic, water, lemon zest and juice, salt, and crushed red pepper flakes, and process until smooth, stopping as needed to scrape down the sides with a flexible spatula. You should have about 2/3 cup.

Make the sandwiches: Prepare the grill for direct heat (if using a grill pan, see Notes). If using a gas grill, set it to 450 degrees. If using a charcoal grill, fill a chimney starter with charcoal, light it, and when the coals are white-gray with ash, pour them onto charcoal grate, adding more charcoal, if necessary. Put the lid on the grill, making sure the vents are open all the way. When all of the coals are gray and hot, about 15 minutes, your grill should be medium-hot. (Use a grill thermometer, or test the heat by holding your hand, palm-down, about 4 inches from the grate, making sure that nothing flammable, such as clothing, is near the heat. If you can hold it there for about 4 seconds, the heat should be at medium, or about 450 degrees.) Pull your hand away from the heat before it gets painful.

Lightly brush both sides of the fish and onion rounds with the oil and season one side with the salt and pepper.

Place the fish and onion on the grill, and cook until grill marks form on the bottom, the onion softens and the fish is no longer translucent and flakes easily under the tines of a fork, 2 to 3 minutes per side for the onion and 3 to 4 minutes per side for the fish. Try not to move the fish too much, as it may fall apart.

Toast the buns either on the grill or grill pan, or in a toaster.

To assemble the sandwiches, spread about 1 tablespoon of the salsa verde onto the bottom side of each bun. Top each with a piece of fish. (If you prefer, trim the fish as needed to fit nicely in the bun.) Top with another 1 tablespoon of the salsa verde, then pile with the grilled onions, lettuce — gently crack on the ribs so the leaves lay flat — and the tops of the buns.

Substitutions: Gluten-free? Use gluten-free hamburger buns in place of regular buns. Parsley can sub with cilantro, and lemon with lime. Don’t care for anchovies? Skip them or add capers to taste. Red onion can be replaced with an onion of your choosing.

Variations: To make this on a grill pan: Preheat a grill pan over medium-high heat. Brush both sides of the fish and the grill pan with oil. Working in batches, if necessary, place the fish and onion on the pan, and cook until grill marks form on the bottom, the onion softens, and the fish is no longer translucent and flakes easily under the tines of a fork, 2 to 3 minutes per side for the onion and 3 to 4 minutes per side for the fish. Try not to move the fish too much, as it may fall apart.

Notes: When choosing the oil for grilling, opt for one that’s suitable for high-heat cooking (with a high smoking point) such as avocado or canola.

Nutrition per serving (1 sandwich, using 4-ounce fillets, plus 2 tablespoons salsa verde): 402 calories, 14g carbohydrates, 53mg cholesterol, 31g fat, 1g fiber, 22g protein, 5g saturated fat, 420mg sodium, 4g sugar

Ellie Krieger is a registered dietitian nutritionist and cookbook author who hosts public television’s “Ellie’s Real Good Food.” Learn more at www.elliekrieger.com.