- 1/4 small red onion, sliced
- 3 tablespoons red wine vinegar
- 1 tablespoon olive oil
- 1 pound boneless, skinless bass fillet
- 1 teaspoon crushed fennel seeds
- kosher salt and black pepper
- 1/2 cup plain yogurt
- 2 tablespoons prepared horseradish
- 2 tablespoons chopped capers
- 4 slices rye bread
- fresh dill leaves, for serving
- Combine the onion and vinegar in a small bowl. Let sit, stirring occasionally, until soft, 13 to 15 minutes.
- Meanwhile, heat the oil in a large nonstick skillet over medium-high heat. Season the fish with the fennel seeds and ¾ teaspoon each salt and pepper.
- Cook until opaque throughout, 2 to 3 minutes per side. Transfer to a plate and break into pieces.
- In a separate bowl, combine the yogurt, horseradish, and capers.
- Spread the horseradish yogurt on the bread and top with the fish, onion, and dill leaves, dividing evenly.