- 2 red chiles (such as Fresno)
- 2 tablespoons coriander seeds
- 2 tablespoons cumin seeds
- 1/2 preserved lemon, flesh removed
- 2 garlic cloves
- 1 cup olive oil
- 2 tablespoons tomato paste
- Kosher salt, freshly ground pepper
- 4 (8-ounce) swordfish fillets (about 1-inch thick)
- 2 tablespoons vegetable oil
- Heat broiler. Broil chiles on a foil-lined baking sheet, turning occasionally, until blackened all over, 6–8 minutes. Transfer to a bowl, cover with plastic wrap, and let sit 15 minutes. Peel and set aside.
- Toast coriander and cumin seeds in a dry small skillet over medium heat, tossing until fragrant, about 2 minutes. Transfer spices to a blender and let cool. Add preserved lemon peel, garlic, olive oil, tomato paste, and reserved chiles and blend until smooth. Transfer harissa to a small bowl; season with salt and pepper. Set 1/4 cup harissa aside for serving.
- Season swordfish with salt and pepper and place in a large baking dish. Coat with remaining harissa; cover and chill at least 1 hour and up to 1 day.
- Heat vegetable oil in a large nonstick skillet over medium. Working in batches if needed, cook swordfish until cooked through (fish will feel firm when pressed), about 3 minutes per side. Transfer to a platter and serve with reserved harissa.