In a medium bowl combine mayonnaise, mustard, prepared horseradish, lemon juice, chopped capers, chopped pickles, hot sauce, paprika, Worcestershire sauce, minced parsley, salt and black pepper. Stir until smooth and well combined.

Taste and adjust seasoning — add a little more lemon for brightness, hot sauce for heat, or salt if needed. Cover and refrigerate at least 30 minutes (or up to 24 hours) to let flavors meld.

Oysters (prep and fry)

Shuck and prepare oysters

If oysters are not already on half shells, carefully shuck them leaving each oyster in its bottom half shell. Rinse briefly under cold water to remove grit and pat shells and oysters dry with paper towels. Keep them chilled on a tray over ice while you prepare the dredge.

Make dredge and coating stations

In a shallow bowl or plate whisk together the flour, cornstarch, cornmeal, kosher salt, black pepper, garlic powder, smoked paprika and cayenne. In a second shallow bowl whisk the buttermilk and beaten egg until combined. Place the seasoned breadcrumbs in a third shallow plate.

Coat oysters

Working one at a time, gently lift each oyster from its shell (leave it in the bottom shell for frying) and dip the oyster meat into the buttermilk-egg mixture to wet thoroughly. Transfer the oyster to the flour mixture and lightly coat, tapping off excess. Return briefly to the buttermilk, then press into the panko breadcrumbs to form an even outer crust. Place coated oysters back into their half shells on a baking sheet. Repeat with remaining oysters.

Heat oil

Pour oil into a heavy skillet or deep pot to a depth of about 1 to 1-1/2 inches (enough to shallow fry) and heat over medium-high until it registers 350°F (175°C) on a deep-fry thermometer. If you don't have a thermometer, a small piece of bread should sizzle and turn golden in about 45–60 seconds.

Fry oysters

Working in batches (do not overcrowd), carefully slide 3–4 oysters in their shells, breaded side up, into the hot oil using tongs. Fry 2 to 3 minutes until golden brown and crisp; flip if necessary to brown evenly (shells provide structure so be careful handling). Internal oysters cook quickly — do not overcook. Use a slotted spoon or tongs to transfer fried oysters to a wire rack set over a baking sheet or paper towels to drain. Keep warm in a 200°F (95°C) oven while frying remaining oysters.

Finish and plate

Arrange warm fried oysters on a platter or individual appetizer plates (3 oysters per half order, or 6 for full). Spoon a generous dollop of remoulade beside each portion or pass in a small ramekin. Garnish with chopped parsley and lemon wedges. Serve immediately so crust remains crisp.