In a large skillet, melt 2 tablespoons of the butter over medium-high heat. Add the garlic and cook, stirring, until soft and fragrant, about 1 minute. Add the watercress, 1/4 teaspoon salt, and pinch white pepper, and cook, stirring, until the watercress is wilted and tender, 2 to 3 minutes. Remove from the heat and cover to keep warm.
Lightly season both sides of the scallops with salt and white pepper. Heat the oil in a large skillet or saute pan over medium-high heat. Add the scallops and cook until golden and just cooked through, about 2 minutes per side. Transfer to a plate and cover to keep warm.
Add the shallots to the oil remaining in the pan, and cook, stirring, until soft, about 1 minute. Add the Champagne and bring to a boil, scraping up any brown bits clinging to the bottom of the pan, and cook until reduced by 50 percent in volume. Add the remaining butter, 1 piece at a time, taking the skillet from the heat as necessary to prevent the sauce from breaking, and cook, whisking constantly, until all the butter is incorporated. Season, to taste, with salt and pepper.
Divide the wilted watercress among 4 serving plates, top each with 5 sauteed scallops, and drizzle with the Champagne Butter Sauce. Serve immediately with the Parmesan Crisps.
Cook and Pair with: Charbaut Brut Champagne, Epernay, France
Yield: 4 servings