To store leftover peppercorn steaks, wrap them tightly in aluminum foil or place them in an airtight container and refrigerate for up to 3 days. For the red wine sauce, use a separate airtight container in the fridge. When you're ready to reignite the flavors, gently reheat the steaks in a skillet over medium heat until just warmed through, and simmer the sauce on low heat, stirring occasionally until heated to your liking.