Martha likes how Emeril fries oysters and has adapted his technique for her Fried Oyster Po' Boy.
Mix together buttermilk, cayenne pepper, 1 teaspoon salt, and 1/2 teaspoon pepper in a medium bowl. Add oysters and turn to coat; let stand 5 minutes. Meanwhile, in a shallow dish, mix together cornmeal, flour, 1 teaspoon salt, 1/2 teaspoon pepper, and a pinch of cayenne; set aside.
In a medium heavy-bottomed saucepan with high sides, heat oil to 350 degrees on a deep-fry thermometer.
Dredge oysters in cornmeal mixture, shaking off any excess. Working in batches, quickly and carefully add oysters to hot oil and cook, turning, until golden, 2 to 3 minutes. Using a slotted spoon, transfer oysters to a plate lined with paper towels; season with salt.
Meanwhile, heat a large skillet over medium heat. Spread butter on both sides of hot dog buns and place in the skillet on their sides, turning, until evenly browned.
Spread tartar sauce in the bottom of each bun. Top with fried oysters, and serve immediately with lemon wedges.