Crush peppercorns by gently pounding them in a zip-top bag with a rolling pin to achieve coarse bits.

After removing your steak from the pan to rest, reduce the heat to medium-low. Add 1 tablespoon of butter and the chopped shallot. Cook for 1 to 2 minutes until fragrant.

Stir in the crushed peppercorns and cook for another 30 seconds to bloom their flavor.

Deglaze the pan with brandy or cognac, if using, and let it bubble for 45 to 60 seconds while scraping up the browned bits.

Pour in the beef stock and simmer for 2 to 3 minutes until reduced by about half.

Add the heavy cream and Dijon mustard. Simmer gently for 3 to 5 minutes until thickened enough to coat the back of a spoon.

Turn off the heat and stir in the remaining 1 tablespoon of butter for a glossy finish. Taste and add salt if needed.

Spoon the sauce over sliced steak immediately. If it thickens while standing, whisk in a splash of stock or water to loosen.