The spice rub can be stored in an airtight plastic container for up to 1 month.
1 teaspoon cumin seed
1 teaspoon fennel seed
1 teaspoon dried oregano
1 teaspoon dried thyme
2 teaspoons paprika
1 /2 teaspoon ground cayenne pepper
2 teaspoons coarse salt
1 /2 teaspoon freshly ground black pepper
2 tablespoons prepared horseradish
1 /4 cup plain low-fat yogurt
1 tablespoon honey
4 4-ounce salmon fillets, skin removed
4 slices crusty bread
1 bunch arugula, stems trimmed
1 /2 small red onion, thinly sliced crosswise
How to make
Blackened salmon sandwiches
Place the cumin seed, fennel seed, oregano, and thyme in a spice grinder. Pulse until finely chopped but not powdery. Transfer to a small bowl; stir in the paprika, cayenne pepper, 11 /2 teaspoons salt, and 1 /4 teaspoon black pepper; set aside.
In another small bowl, whisk together the horseradish, yogurt, honey, remaining 1 /2 teaspoon salt, and 1 /4 teaspoon pepper; set aside.
Heat a heavy skillet over medium-high heat. Coat each fillet with 2 teaspoons spice blend; pat with your fingers. Place the fillets in the hot skillet. Cook until well browned, about 5 minutes. Flip the fillets; cook through, about 5 minutes more. Transfer to a plate; set aside.
To assemble, spread the bread with the horseradish mixture. Top with arugula and onion. Flake the salmon into chunks; place on the sandwiches. Drizzle with the remaining horseradish mixture; serve immediately.