This classic French dish reminds me of something one might have ordered in the sort of elegant, old-school French restaurant of generations past. Consider it retro-romantic, but like many great French classics, it is so worth revisiting. While I don't see a lot of Worcestershire in France, their grocery stores do stock it, and I've found that this touch adds much depth to the sauce.
Season both sides of the steaks with salt and pepper, to taste. In a large skillet, melt 1 tablespoon of the butter over medium-high heat. Add the steaks and cook, turning as needed, to the desired doneness (10-12 minutes for medium-rare).
Reduce heat as necessary if the meat browns too quickly. Transfer the steaks to a platter and cover with foil to keep warm. Add the shallot to the skillet and sauté briefly until translucent. Remove the pan from heat and add the broth and brandy, taking care not to let the liquid splatter.
Return the pan to the stove and bring to a boil over high heat, stirring with a whisk to loosen any browned bits from the bottom of the pan. Boil until the liquid is reduced to 1/3 cup, about 2-3 minutes depending on the stove and the pan size.
Whisk in the mustard and Worcestershire sauce. Then, whisk in the remaining butter. Season with additional salt and pepper, to taste. Arrange the steaks on 4 dinner plates, spoon the sauce over the steaks, top with the parsley, and serve.