Take out 4 beef tenderloin steaks and let them sit at room temperature for 30 minutes. Mince 1 small shallot and coarsely crush 2 tablespoons whole peppercorns. Season steaks with 1 teaspoon kosher salt, pressing crushed pepper onto both sides.

Heat a large cast iron or stainless steel skillet over high heat. Add 1 tablespoon olive oil and 1 tablespoon unsalted butter. Cook steaks until medium-rare with a brown crust (2-3 minutes per side). Transfer to a plate, cover with foil.

Reduce heat to medium. Add 1 tablespoon unsalted butter and shallot. Sauté until shallot is translucent (about 1 minute). Remove from heat, add 1/4 cup Cognac, return to medium heat, and simmer until mostly evaporated (1-2 minutes).

Add 1/2 cup beef stock, increase heat, and simmer until slightly reduced (2-3 minutes). Incorporate 1/2 cup heavy cream and 1 tablespoon unsalted butter. Stir until the sauce thickens (2-3 minutes). Stir in accumulated steak juices. Serve steaks on a sauce bed, spooning more on top.