Preheat a grill to medium-high.
Shrimp-Lemon Butter Sauce: Combine the wine, lemons, shallots, and garlic in a medium saucepan and bring to a boil. Reduce the heat to medium-low and simmer until reduced by half, about 20 minutes, stirring occasionally and mashing the lemons with the back of a spoon to break up into pieces. Add the cream and cook until reduced by half, about 3 minutes.
Whisk in the butter, 1 tablespoon at a time, adding each piece before the previous one has been completely incorporated. Continue until all the butter is incorporated and the sauce coats the back of a spoon, removing the pan from the heat periodically to prevent the sauce from getting too hot and breaking. Add the salt and pepper, and whisk to blend.
Remove from the heat and strain, pressing down with the whisk, through a fine mesh strainer, into a small bowl. Fold in the parsley and cover to keep warm.
Season the shrimp with the Essence. Melt the remaining 1 teaspoon of butter in a medium-non-stick skillet over medium-high heat. Add the shrimp and cook, stirring, until pink and cooked through, about 3 minutes.
Remove from the heat and fold into the sauce. Serve immediately with the pompano.
Combine the oil and Essence in a small bowl, and lightly rub both sides of each fillet with the mixture.
Place the fish, flesh side-down on the grill and cook for 2 minutes. Turn the fillets 1/4-turn to make decorative grill marks and cook an additional 2 minutes. Turn and cook skin side-down until fish flakes easily, about 4 minutes.
Remove from the grill and place on 4 serving plates. Top with the butter sauce, and serve immediately. (Alternately, the fish can be cooked in the oven. Preheat the oven to 375 degrees F. Place the seasoned fish on a non-stick baking sheet and roast until golden brown and cooked through, 10 to 12 minutes.)
Trim the leeks, discarding the green tops. Cut into thin strips and place in a bowl of ice water. Soak for 5 minutes to remove any grit, then drain. Place in a clean bowl of ice water and soak again for 5 minutes. Drain well.
Combine the stock, wine, lemon peel, bay leaves, and pepper in a medium saucepan. Bring to a boil. Reduce the heat to medium-low. Add the leeks and simmer until tender, about 10 minutes. Remove from the heat and let the leeks sit in the poaching liquid for 10 to 15 minutes.
Drain in a fine mesh strainer. Discard the bay leaves and reserve the poaching liquid, as desired, for another use. Set aside the leeks until ready to serve.