Tenderize the steaks by pounding with a meat mallet to about 1/2-inch thickness.

Season both sides of each steak generously with salt and pepper.

Heat olive oil in a skillet over medium-high heat until shimmering.

Sear steaks in the hot skillet for 3-4 minutes per side for medium-rare (internal temperature 130°F), adjusting time for desired doneness.

Remove steaks from the skillet and let rest, covered loosely, for 5 minutes.

Reduce heat to medium and add butter and shallots to the skillet; sauté for 2 minutes until fragrant.

Add mushrooms and cook for 3 minutes until they are tender and browned.

Carefully deglaze the pan with brandy, scraping up any browned bits from the bottom of the skillet.

Stir in beef broth and Dijon mustard, then simmer the sauce for 2-3 minutes until slightly thickened.

Return the steaks to the skillet and spoon the sauce over them; heat through for 1 minute.

Sprinkle chopped parsley over the steaks and serve immediately.