Rub the venison medallions dry, sear in hot clarified butter on both sides for about 4 minutes. Season with salt and pepper. Extinguish with a dash of nut liqueur. Add the walnuts and simmer until creamy. If you want more gravy, you can add game stock (ready from the jar) or make more of the same from leftover game.
Tip: Instead of clarified butter, you can also use butter in most cases.