3 tablespoon all-purpose flour
1 teaspoon kosher salt, plus more as needed
1/2 teaspoon finely grated lemon zest
1/4 teaspoon freshly ground black pepper, plus more as needed
6 ounces thick-cut bacon, cut into lardons (about 1/8-inch thick and 1-inch long)
12 wild leeks, cut into 2-inch lengths, bulbs separated from leaves, or garlic scapes or green onions
6 pickerel filets (about 4 to 6 ounces each)
3 tablespoon unsalted butter
1 tablespoon grapeseed oil
1/4 cup dry white wine
1/4 cup fish stock or clam juice
1 lemon, cut into 8 wedges
In a medium bowl, whisk together the flour, salt, lemon zest and pepper; set aside. Heat a large, heavy skillet (preferably cast iron) over medium heat until very hot. Add the bacon and cook, stirring occasionally, until crisp. Using a slotted spoon, transfer the bacon to a medium bowl, keeping the bacon drippings in the skillet. Add the wild leek bulbs to the skillet and cook, stirring constantly, for 2 minutes. Using a slotted spoon, transfer the wild leek bulbs to the bowl with the bacon.
Dredge the pickerel filets in the flour mixture, shaking off any excess. Add 1 tablespoon of the butter and the oil to the hot pan and carefully place the pickerel filets, skin side down, in the pan. Allow the fish to cook, without disturbing it, until the flesh is almost opaque and the skin can be lifted from the pan without resistance, about 3 minutes. Using a flexible metal spatula, carefully lift each filet from the pan and turn it over. Cook until just opaque, about one to 2 minutes. (See Doneness Tip, below.) Remove the fish from the pan and keep warm.
Add the wine and fish stock to the pan. Cook the liquid, scraping up the brown bits from the bottom of the pan with a whisk, until the liquid has been reduced by two-thirds. Whisk in the remaining 2 tablespoons of butter. Stir the reserved bacon and wild leek bulbs and the wild leek leaves into the pan sauce to warm them through, 1 to 2 minutes. Season the sauce with salt and pepper, to taste. Add a squeeze of lemon, if desired. Place a pickerel filet skin-side up onto each plate and spoon a generous amount of the bacon and leek mixture over top. Serve immediately with the lemon wedges.
Doneness tip: If in doubt as to the doneness of the fish, here’s a foolproof way to check: Insert a metal skewer or the tip of a paring knife into the thickest part of the filet. Hold for 3 seconds and then touch the tip of the knife to your wrist. If it feels very warm, the fish is done.