In a large saute pan, heat the olive oil. When the oil is hot, add the shallots and saute for 1 minute. Add the garlic and crawfish tails and continue to saute for 2 minutes. Season the tails with Essence. Add the green onions. Stir in the cream and bring the liquid to a boil. Reduce the heat to a simmer and cook until the liquid thickens and coats the back of a spoon, about 4 minutes. Place the fillets in a glass bowl and cover with the buttermilk. Season the mixture with Essence. Cover the bowl with plastic wrap and place in the refrigerator. Marinate the fish for about 30 minutes. Remove the bowl from the refrigerator and drain. In a shallow bowl, combine the flour and cornmeal. Season the flour with Essence. Dredge the fillets in the seasoned flour, coating each side completely. In another large pan, heat the vegetable oil. When the oil is hot, add the fillets and pan-fry for 3 to 4 minutes on each side, or until the fillets are golden brown and the flesh is flaky. Remove the fish from the pan and drain on a paper-lined plate. Season the fillets with Essence. Serve the fish with the sauce spooned over the top.
Combine all ingredients thoroughly.