Servings: Serves 3
To make the mignonette, combine the watermelon juice, champagne vinegar, champagne, horseradish, cucumber, shallots and black pepper in a bowl. Mix until they are completely incorporated. If possible, allow the mignonette to rest overnight in the refrigerator.
Fill a medium-sized bowl with crushed ice, then place the oysters in a circle around the inside of the bowl.
Mix the mignonette well. Serve a tablespoon of the sauce into each oyster. Garnish with chopped tarragon.