Peppercorn sauce for steak is made with peppercorns, butter, and heavy cream. Food Network has simple and easy to follow recipes from two of its stars.
To make Ree Drummond's recipe, crush 4 to 6 tablespoons tri-color peppercorns with a rolling pin in a zip-top bag. In a ovenproof skillet, melt 4 tablespoons butter. Crumble in 1 beef bouillon cube and whisk to combine. Add 4 to 6 tablespoons Dijon mustard and whisk. Add 1 cup brandy and continue to whisk for 45 seconds while it bubbles. Add in 1 1/2 to 2 cups heavy cream or substitute some of the heavy cream for half-and-half and the crushed peppercorns. Whisk it all together and allow to thicken to a desired consistency.
To make Alton Brown's recipe, add 3/4 beef stock or broth to a sauté pan. Allow the liquid to reduce for three to four minutes over medium-high heat. Add 3 tablespoon cognac, 3/4 cup heavy cream and 1 tablespoon drained and crushed green peppercorns in brine. Increase the heat to high and cook while whisking for five to seven minutes, or until the sauce thickens enough to coat the back of a spoon. Season the sauce to taste with salt.