The night before serving, put the fillets in a bowl and pour the buttermilk over all. Toss to coat. Cover and refrigerate.

Preheat the oven to 250°F.

In a pie plate, combine the cornmeal, parsley, oregano, thyme, salt, black pepper, and ground red pepper. Remove the fish from the buttermilk, shaking off any excess. Dip the fish in the cornmeal mixture, turning to coat completely.

Heat 1½ tablespoons of the oil in a large skillet over medium heat. Add 2 fillets and cook for 8 to 10 minutes, turning once, or until browned and the fish flakes easily. Place on a baking sheet and keep warm in the oven. Repeat with 1½ tablespoons more oil and the remaining 2 fillets.

Wipe the skillet clean and heat the remaining 1 tablespoon oil over medium heat. Add the garlic and cook for 2 minutes. Add the tatsoi, lemon juice, and soy sauce and cook for 3 minutes, or until heated through. Transfer to a serving platter and top with the fillets. Sprinkle with the lemon zest.