1 Cup Demi-Glace
2 Tablespoon Dijon Mustard
4 Teaspoons Worcestershire Sauce
2 Teaspoon Tomato Paste
1 Pinch Cayenne Pepper
5 Teaspoons Vegetable Oil
4 (8 Ounce) Beef Tenderloin Steaks, Fully Trimmed, Pounded To 1/2 Inch Thick
Kosher Salt And Freshly Ground Black Pepper, To Taste
6 Tablespoon Unsalted Butter, Cut Into Small Chunks
6 Tablespoons Shallot, Minced
½ Cup Cognac Or Brandy
1 Cup Heavy Cream
6 Teaspoons Sliced Fresh Chives
Step 1 Season steaks generously on both sides with salt. Allow steaks to come to room temperature while you make the sauce.
Step 2 Stir together demi-glace (see Cook’s Note), mustard, Worcestershire sauce, tomato paste, and cayenne pepper in a bowl.
Step 3 Heat oil in a skillet over very high heat, swirling carefully to evenly cover surface. When oil reaches a smoking point, transfer steaks to oil; add a few chunks of butter. Sear meat on high heat until brown on each side, 2 to 3 minutes per side; keep them on the rare side. An instant-read thermometer inserted into the center should read 125 degrees F (52 degrees C). Transfer steaks to a warm plate.
Step 4 Stir shallots into skillet; cook until softened, 2 to 3 minutes. Remove skillet from heat; pour in Cognac. Carefully ignite with a fireplace lighter. When alcohol burns off and flames go out, return skillet to high heat and bring to a boil; cook, stirring, a few minutes to reduce slightly. Add demi-glace mixture, cream, and any accumulated juices from the steak. Cook on high heat just until sauce starts to thicken, 3 to 5 minutes. Transfer steaks back to pan and reduce heat to low. Gently simmer until meat is heated through and cooked to your desired level of doneness.
Step 5 Transfer to hot plates and serve with a generous spoonful or two of sauce. Sprinkle with chives. Serves 4
Note: Notes and recipe for Demi-glace to follow.