Begin by placing your beef stock in a small saucepan over medium-high heat. Allow it to come to a gentle boil and let it reduce until only 1/2 cup remains (about 10 minutes).

While the broth reduces, combine the Dijon mustard, soy sauce, and Worcestershire sauce in a small bowl. Whisk until smoothly blended.

Pat your beef tenderloin steaks dry with a paper towel. Season generously with kosher salt and freshly ground black pepper.

In a large skillet, heat the olive oil over medium-high heat. Add the butter, and once it stops sputtering, add the seasoned steaks.

Cook the steaks without moving them for about 2 minutes on one side until a crust forms. Flip the steaks, lower the heat to medium.

Add the smashed garlic and thyme to infuse their flavors. Cook the steaks for another 2 minutes, basting them with the melted butter.

Remove the cooked steaks from the skillet and place on a plate. In the same pan, add the minced shallots and the white parts of the scallions, sauté for about 1 minute.

Add the minced garlic and cook for another minute.

Deglaze the pan with the alcohol-free Cognac, simmer until almost fully evaporated.

Pour in the reduced beef broth and the Dijon mixture. Stir and simmer for 1 minute before whisking in the heavy cream. Let it thicken for 2 minutes.

Return the steaks to the skillet along with any accumulated juices, and heat through for about 2-3 minutes.

Garnish with chopped parsley and the green parts of the scallion. Serve immediately with fluffy mashed potatoes or steamed vegetables.