Temper steaks at room temperature for 30 minutes prior to cooking.
Season steaks on all sides with kosher salt and press the coarsely crushed peppercorns into the surface to form an even crust.
Heat a heavy stainless steel or cast iron skillet over medium-high heat with the neutral oil.
Sear the steaks for 4 to 5 minutes per side for medium-rare, or until the internal temperature reaches 130°F (54°C).
Transfer steaks to a warm plate and tent loosely with aluminum foil to rest for 5-10 minutes.
Drain excess fat from the skillet, leaving approximately 1 teaspoon of oil and the fond.
Reduce heat to medium, add 1 tablespoon of butter, and sauté the minced shallots for 2 minutes until translucent.
Deglaze the pan with cognac, scraping the bottom to release the fond; simmer until the liquid is reduced by half.
Whisk in the beef stock and Dijon mustard, then simmer until reduced by half again.
Incorporate the heavy cream and continue to simmer until the sauce thickens to a nappe consistency (coats the back of a spoon).
Whisk in the remaining 1 tablespoon of cold butter to emulsify and adjust seasoning with salt to taste.
Plate the rested steaks and pour the peppercorn cream sauce generously over the top.