Tortilla-Crusted Tilapia With Pickled Red Onions and Crema

A kind of Mexican sour cream, crema is increasingly available at U.S. supermarkets. If you can't find it, sour cream or creme fraiche diluted with a bit of milk, cream or water will do.

Ingredients

For the fish:

• Two 1/2-pound tilapia fillets
• 1 teaspoon kosher salt
• 2 tablespoons lime or lemon juice
• 2 tablespoons vegetable oil, preferably grapeseed
• 2 cups tortilla chips
• 2 teaspoons chili powder

For the pickled onions:

• 1 medium red onion, sliced 1/4-inch-thick
• 3/4 cup distilled white vinegar
• 1/4 cup orange juice
• 1 1/2 tablespoons sugar
• 3/4 teaspoon kosher salt
• 1/2 teaspoon cumin seeds
• 1/2 teaspoon dried oregano
• 2 tablespoons chopped pickled jalapenos

To finish:

• 1 tablespoon unsalted butter, melted
• Crema or sour cream, to serve

Instructions

1. To prepare the fish, cut each fillet down the center seam to separate the thin half of the fillet from the thick half. Cut each of the pieces in half crosswise (for a total of 8 pieces). Sprinkle the fish pieces with the salt, then transfer to a zip-close plastic bag. Add the lime or lemon juice and oil. Refrigerate for 30 minutes, turning the bag several times.
2. While the fish is marinating, in a large, wide bowl finely crush the tortilla chips (with a few larger pieces, it should not be a powder) and toss with the chili powder. Set aside.
3. To make the pickled onions, in a small saucepan over medium-high, combine the red onion, vinegar, orange juice, sugar, salt, cumin and oregano. Bring to a boil and simmer for 5 minutes. Set aside and let cool. Drain the mixture and chop the onions. In a small bowl, combine the onions with the jalapenos.
4. Heat the oven to 375 degrees. Line a rimmed baking sheet with kitchen parchment.
5. Remove the fish pieces from the marinade and arrange in a single layer on the prepared baking sheet. Keep the thin pieces on one side and the thick pieces on the other. Pack the tortilla crumbs on top of the fillets, then drizzle the crumbs with the melted butter. Bake the fish on the oven's middle rack until it is just cooked through, about 5 minutes for the thinner pieces and 8 minutes for the thicker pieces.
6. Transfer a thick and a thin fillet piece to each of 4 serving plates. Serve each portion topped with some of the pickled onions and the crema.