In a large skillet, heat the vegetable oil until shimmering. Dip each flounder fillet in the buttermilk mixture, let the excess drip off then carefully coat the fillet in the cornmeal. Fry the flounder over moderate heat until golden brown and crisp, about 4 minutes per side. Transfer the fillets to paper towels to drain, then transfer to plates. Serve the flounder with the asparagus and pancetta.