Remove steaks from refrigeration 30 minutes prior to cooking to reach room temperature.

Season both sides of the steaks with salt, then press the crushed peppercorns firmly into the meat surface.

Heat olive oil and butter in a heavy-bottomed stainless steel or cast iron skillet over medium-high heat until the butter foam subsides.

Place steaks in the skillet and sear for 4 to 5 minutes per side for medium-rare, aiming for an internal temperature of 130°F (54°C).

Transfer steaks to a warm plate and tent loosely with foil to rest.

Add minced shallots to the remaining fat in the skillet and sauté for 1 minute until translucent.

Remove the pan from the heat source and carefully add the Cognac; return to heat and deglaze the pan, scraping the fond from the bottom.

Whisk in the beef stock and reduce the liquid by half over high heat.

Lower the heat and whisk in the heavy cream and Dijon mustard; simmer for 2 to 3 minutes until the sauce coats the back of a spoon.

Plate the steaks and pour the peppercorn sauce generously over the meat.