In a skillet, melt the butter over medium heat. Add the finely chopped shallot and minced garlic, and sauté for about 2 minutes, or until they become translucent.
Carefully add the brandy or cognac to the skillet, and let it simmer for a minute or two to cook off the alcohol.
Stir in the heavy cream, green peppercorns, coarsely crushed black peppercorns, and Dijon mustard. Reduce the heat to low and let the sauce gently simmer for about 5 minutes, or until it thickens slightly.
Add the beef stock (or chicken stock) to the sauce and continue to simmer for an additional 2-3 minutes, or until the sauce reaches your desired consistency.
Taste the sauce and add salt as needed. Remember that the peppercorns will provide some saltiness, so be cautious not to over-salt.
Remove the skillet from the heat and serve the creamy peppercorn sauce immediately over your favorite steak.
Prep Time: 5 minutes | Cooking Time: 15 minutes | Total Time: 20 minutes

Kcal: Approximately 300 kcal | Yield: 4 servings