Step 1

in a small bowl, mix the mayonnaise, cornichons, pickled onions, tarragon, and lemon juice. Season with salt and pepper, taste for seasonings, then stir again to combine. Place in the fridge to keep cool.

Step 2

Season the fish with salt and pepper on both sides. Let sit to warm up to room temperature.

Step 3

Place the breadcrumbs in a small casserole dish or shallow bowl. In another casserole or bowl, whisk the egg and milk to combine. In yet another small casserole or bowl, combine the flour, paprika, and garlic powder.

Step 4

Heat the oven 250°F to keep the fish warm while you fry. Dredge the fish in the seasoned flour to coat, shaking off any excess. Dip into the egg wash, making sure to get the egg wash under your fingers where you're holding the fish, shaking off any excess. Dredge in the breadcrumbs, making sure all sides are coated. Let sit in the crumbs until you're ready to fry.

Step 5

Heat a large heavy pan over medium heat. Pour in enough oil to coat the bottom of the hot pan. The oil should gently shimmer, not quake nor smoke. Add the butter, swirling the pan to distribute, and heat until foamy.

Step 6

Fry the fish on both sides. If you think or feel nervous about them browning too fast or not being done in the middle, let them finish baking in the oven. Transfer the fish to a wire rack set inside a rimmed baking sheet, then place in the oven to keep warm.

Step 7

Serve hot with a dollop of tartar sauce and a lemon wedge.