12 oz. Pappardelle's Lobster Ravioli
1 whole vanilla bean, split
1/2 c. champagne
1/4 c. champagne vinegar
1/2 tablespoon minced shallots
8 oz. cold butter, cut in pieces
1 tablespoon crème fraîche
Salt, to taste
1/4 c. hazelnuts, chopped and toasted