Prosecco Mignonette

Name: Prosecco Mignonette
Yield: Makes 3 1/2 cups
Ingredients: 3 shallots, very finely chopped; 2 cups champagne vinegar; 1 cup prosecco; 2 tablespoons black peppercorns, coarsely ground; 1 sprig fresh tarragon, leaves only, coarsely chopped; Pinch of sea salt