How to Make It
In a small bowl, whisk the mayonnaise and buttermilk. Fold in the Green Tomato Pickles, season the sauce with salt and pepper and refrigerate until chilled.
Put the butter- milk and flour in 2 separate pie plates. Whisk the cornmeal into the flour along with the salt and pepper. Dip the fish fillets on both sides in the buttermilk, allowing the excess to drip back into the pie plate. Dredge the fish in the flour mixture, pressing to help it adhere. Transfer the fish to a baking sheet.
Heat 1/4 inch of vegetable oil in each of 2 large skillets until shimmering. Sprinkle the fish with more of the flour mixture and add the fillets to the skillets, skin side up. Cook over moderately high heat, turning once, until golden and cooked through, 5 to 6 minutes. Drain the fish on a paper towellined baking sheet. Serve right away, with the tartar sauce.