Combine shallots, vinegar, and tarragon in an 8- to 10-inch frying pan. Boil over high heat, stirring often, until all the liquid evaporates, about 2 minutes.
Add 1/2 cup cream, peppercorns, and mustard. Boil, stirring often, until cream turns a golden brown, about 8 minutes. Stir in cognac and remaining cream. (If making ahead, set aside up to 2 hours, or cover and chill up to 1 day.)
Heat sauce, stirring, until it boils. Add salt to taste.
Nutritional analysis per tablespoon.
0 servings
* The % Daily Value (DV) tells you how much a nutrient in a serving of food contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.