How to Make It
Cook the fries according to the package directions.
Meanwhile, heat 1 tablespoon of the oil in a large skillet over medium-high heat.
Season the steak with ½ teaspoon salt and ¼ teaspoon pepper and cook to the desired doneness, 2 to 3 minutes per side for medium-rare. Let rest 5 minutes before slicing.
Remove the skillet from heat and carefully add the cognac. Return to the heat and cook, stirring occasionally, until thickened, 2 to 3 minutes. Add the cream and cook until thickened, 2 to 3 minutes more.
Meanwhile, toss the romaine, onion, blue cheese, vinegar, the remaining 2 tablespoons of oil, and ¼ teaspoon each salt and pepper in a large bowl. Serve with the steak, sauce, and fries.