Chef John's Fisherman's Pie

Prep time: 15 min
Cook time: 70 min
Servings: 6
Yield: 6 servings

Description

My fisherman's pie gives you flaky cod mingled with spinach in a garlic and lemon sauce underneath a browned crust of creamy, buttery potatoes. It tastes fantastic.

Ingredients

3 russet potatoes, peeled and cut into chunks
3 tablespoons butter
1 pinch freshly grated nutmeg
salt and ground black pepper to taste
1 pinch cayenne pepper, or to taste
1/2 cup milk
2 teaspoons olive oil
12 ounces baby spinach leaves
3 tablespoons butter
3 tablespoons all-purpose flour
2 cloves garlic, minced
2 cups cold milk, divided
2 teaspoons lemon zest
1 tablespoon butter
salt and ground black pepper to taste
1 pinch cayenne pepper, or to taste
2 pounds boneless cod fillets
1/2 lemon, juiced
1 tablespoon chopped fresh chives for garnish

Directions

1 Bring a large saucepan of salted water to a boil; add potatoes to boiling water and cook until very tender, about 20 minutes. Drain well. Mash in 3 tablespoons butter until thoroughly combined. Season with nutmeg, salt, black pepper, and cayenne pepper. Mash 1/2 cup milk into potato mixture until smooth.
2 Drizzle olive oil in a large Dutch oven over medium-high heat, add spinach, and season with a big pinch of salt. Cook, stirring occasionally, until spinach has wilted, about 1 minute. Transfer to a bowl lined with paper towels to wick away excess moisture.
3 Heat 3 tablespoons butter and flour in a saucepan over medium heat; whisk mixture to a smooth paste. Cook, stirring constantly, until mixture has a nutty smell and is slightly browned, about 2 minutes. Add garlic; whisk until fragrant, 10 to 20 seconds.
4 Whisk 1 cup cold milk into flour mixture; cook until thickened. Whisk in remaining 1 cup milk and lemon zest. Bring white sauce to a gentle simmer, whisking constantly; season with salt. Turn heat to very low and keep sauce warm.
5 Preheat the oven to 375 degrees F (190 degrees C). Grease an 8x12-inch casserole dish with 1 tablespoon butter.
6 Season buttered pan with salt, black pepper, and cayenne pepper. Lay boneless cod fillets into the pan in a single layer. Season tops of fillets with more salt, black pepper, and cayenne pepper. Spread spinach evenly over fish and drizzle with lemon juice. Spoon white sauce over spinach; give casserole dish several taps and shakes to eliminate bubbles.
7 Drop mashed potatoes by heaping spoonfuls over the casserole and spread smoothly to cover. Place dish onto a rimmed baking sheet to catch spills.
8 Bake in the preheated oven until bubbling, about 40 minutes. Turn on the oven's broiler and broil until potato crust has a golden brown top, about 2 minutes. Fish should flake easily. Let stand 10 minutes before serving. Garnish with a sprinkle of chives.