Cook the pasta in a large pot of boiling salted water until al dente, about 8 minutes. Drain, reserving 1/4 cup of the cooking liquid. Return to the pot and toss with the olive oil and reserved cooking liquid. Cover to keep warm.
In a large saute pan or skillet, melt the butter over medium-high heat. Add the onions and cook, stirring, until soft, about 5 minutes. Add the garlic, Essence, salt, and cayenne, and cook, stirring, for 1 minute. Add the white wine and cook over high heat until nearly all evaporated. Add the cream lemon juice and cook, stirring occasionally, until slightly reduced. Add the crawfish tails and cook, stirring, to warm through. Add the onions and parsley and cook for 1 minute. Add the cooked pasta and toss to coat with the sauce. Cook until the pasta is warmed through, about 1 minute. Remove from the heat and add 1/2 cup of the cheese.
Turn out into a serving bowl and top with the remaining 1/2 cup of cheese. Serve.
Combine all ingredients thoroughly.
*Peeled medium shrimp can be substituted, but the cooking time must be increased to allow thorough cooking.
Recipe from Emeril Lagasse