Sauté shallots in 30g butter. Add Vermouth and reduce until shallots are barely wet. Add cream and reduce by half. Add
Glace de Poulet Gold®
and whisk until dissolved. Add tarragon and mustard. Stir in remaining butter 15g at a time, swirling constantly to incorporate the butter slowly into the sauce. Sauce will break if boiled too rapidly. Add salt and pepper to taste. Serve over grilled chicken or fish.