Preheat the oven to 375 degrees F.
In a bowl, toss the sweet potato cubes with the oil and 1 teaspoon of the garlic. Season lightly with Essence, salt and pepper, tossing to coat evenly. Arrange in a baking dish and roast, stirring occasionally, until the potatoes are tender, 25 to 30 minutes. Let cool.
To make the dressing, in a medium bowl, whisk together the buttermilk, sour cream, lime juice, and hot pepper sauce, if desired. Add the green onions, parsley, and remaining 2 teaspoons garlic. Adjust the seasoning, to taste, with salt and pepper.
In a large bowl, toss the crawfish with enough dressing to lightly coat, 1/2 to 3/4 cup. Adjust the seasoning, to taste.
Arrange the lettuce on 4 large salad plates. Place the crawfish salad in the center of the lettuce and arrange the roasted sweet potatoes around the crawfish. Garnish with the fried orka and drizzle to taste with the remaining buttermilk dressing. Serve immediately.
Yield: 4 servings