1/2 cup minced shallots
1/4 cup white vinegar
1/4 cup unseasoned rice vinegar
1/8 teaspoon sugar
1/8 teaspoon kosher salt
1 1/4 teaspoon finely crushed white peppercorns
Finely mince the shallots by hand or with food processor. Stir in the vinegars, sugar, and salt. Add the freshly crushed white pepper. Stir with a fork. Chill: Cover with plastic wrap and chill in the refrigerator for a minimum of 4 hours. For best results, store for at least 1 day before using. The mignonette flavor will be better blended the longer it sits. You may notice that the crushed white peppercorns may sink to the bottom of the bowl as the mignonette rests. If you see this, just give it a little stir.
Usually, the mignonette sauce is served in a small bowl with a small spoon, alongside the oysters on a platter. You can scoop a small amount of the mignonette (1/8 of a teaspoon or so) onto your oyster before eating. Enjoy!