In the same pan that you cooked the filets, pour in red wine and bring to a boil over high heat, using a spoon or spatula to scrape up any browned bits left from cooking the steaks. Allow wine to reduce by half and thicken slightly, about 3-4 minutes
Add butter into the pan, followed by shallots and garlic, and stir until butter has melted completely into the sauce mixture, about 1 minute more
Taste sauce for seasoning adjustments (additional salt/pepper if needed). You may also add more wine if you feel like you need a little bit more zing
Serve cooked premium filet mignon with warm red wine sauce poured over the top, along with fresh chopped parsley or chives, as garnish if desired