4 (6 ounce) halibut fillets, skin removed
1 ½ teaspoons freshly cracked black pepper, divided
1 ½ teaspoons sea salt, divided
½ cup all-purpose flour
2 eggs, lightly beaten
1 cup panko bread crumbs
Sauce:
2 tablespoons unsalted butter
¼ cup minced shallot
1 teaspoon minced serrano pepper
1 cup half-and-half
1 cup roughly chopped cilantro leaves
1 tablespoon fresh lime juice
½ teaspoon sea salt
¼ cup canola oil
Season halibut fillets all over with 1 teaspoon cracked black pepper and 1 teaspoon sea salt.
Whisk flour, remaining black pepper, and 1/2 teaspoon sea salt together in a shallow bowl. Whisk eggs in another shallow bowl. Pour panko bread crumbs into another shallow bowl.
Gently roll 1 halibut fillet in flour mixture to coat and shake off any excess. Dip 1 side of fillet into egg, then press egg-coated side into bread crumbs to coat evenly. Place fillet, panko-side up, onto a plate and repeat with remaining fillets. Cover the plate loosely with plastic wrap and refrigerate until cold, about 15 minutes.
Melt butter in a small saucepan over medium-high heat. Saute shallot and serrano pepper in hot butter until fragrant, about 1 minute. Stir half-and-half and cilantro leaves into shallot mixture, bring to a simmer, and cook, stirring frequently, until reduced by half, 6 to 8 minutes. Remove from heat; stir in lime juice and remaining 1/2 teaspoon sea salt. Puree sauce using an immersion blender until smooth.
Preheat oven to 300 degrees F (150 degrees C). Line a baking sheet with aluminum foil and place an ovenproof wire rack on the baking sheet.
Heat canola oil in a nonstick skillet over medium-high heat. Place fillets, panko-side down, in hot oil and cook until golden, about 2 minutes. Flip fillets and transfer, panko-side up, to the wire rack on the prepared baking sheet.
Bake fillets in the preheated oven until fish flakes easily with a fork, 6 to 7 minutes. An instant-read thermometer inserted into the center should read 145 degrees F (63 degrees C). Transfer fillets to plates and top with cilantro sauce.
