Ingredients
Salt and freshly ground black pepper
1 (12- to 16-ounce) boneless steak, such as filet mignon or strip steak, about 1-inch thick
2 tablespoons unsalted butter
1 tablespoon neutral oil, such as grapeseed or safflower
2 tablespoons minced shallot or red onion
1 teaspoon tomato paste
2 tablespoons Cognac or brandy
1/4 cup heavy cream
1 teaspoon Dijon mustard
1 teaspoon Worcestershire sauce
1/2 teaspoon fish sauce (optional)
Minced chives or parsley, for garnish
Directions
1
Sprinkle salt and pepper on both sides of the steak and set aside at room temperature for 15 to 30 minutes.
2
Melt the butter and heat the oil in a large skillet set over medium-high. Pat the steak dry with a paper towel. Increase the heat to high, add the steak to the pan and sear until well browned, about 2 minutes. Turn and sear on the other side and cook until done to taste, 1 to 4 minutes longer. If your steak is thick enough, insert an instant-read thermometer in the center to test the temperature: Rare is 125 degrees; medium rare is 135 degrees; medium is 145 degrees. When the steak is done, move it to a cutting board and tent with an overturned bowl or foil to keep warm.
3
Add shallot to the pan and sauté until golden, 2 to 3 minutes on medium-high heat, stirring once or twice. Stir in the tomato paste, mixing well and letting it deepen in color, about 1 minute.
4
Turn off the heat and add the Cognac to deglaze the pan. Using a long match or stick lighter, set the Cognac on fire, standing back and taking care. Let the flames burn out, then turn the heat to medium-high and cook until the Cognac is almost evaporated, 1 to 2 minutes.
5
Stir in the cream, mustard, Worcestershire and fish sauce, if using, and cook until thickened, about 1 to 2 minutes. Drizzle the warm sauce over the steak — you can slice beforehand if you wish — and garnish with black pepper and herbs.