How to Make It
Bring wine, vinegar, shallot, peppercorns, and thyme sprigs to a boil in a medium skillet or saucepan over medium-high. Cook, stirring occasionally, until liquid is reduced to about 2 teaspoons, 5 to 10 minutes.
Reduce heat to low, and whisk in cream. Remove from heat, and gradually whisk in butter, 1 piece at a time, until fully incorporated. Stir in salt. Pour mixture through a fine wire-mesh strainer into a bowl; discard solids. Serve sauce immediately.