In a medium sauce pot, reduce the stock by half. Add the red wine reduction and reduce by half again. Set aside.
Preheat oven 500 degrees.
When ready to cook the meat, scrape all the marinade from meat and sprinkle generously with salt and some cracked pepper. Heat a skillet with the bottom just covered with half of the olive oil and half of the cooking oil. Once the oil is hot, sear the beef tenderloin on all sides until nicely browned.
Place the meat on a pan with a rack on it and cook the beef for about 17 minutes or until the meat reaches 120 degrees. Let rest for at least 5 minutes.
Use the skillet with the searing remnants from the beef. Get or keep the pan hot and deglaze the pan with the stock and wine reduction liquid. Scrape all the meat bits and seasoning into the liquid. Strain the liquid back into your saucepot and place on burner to simmer. Add cocoa powder and whisk until smooth. Add lemon juice and salt. All this reduction and scrapings should now be a glossy viscous, beautiful sauce.
Slice beef into 3 inch medallions and glaze with sauce.
Chef Maurine Sarjeant