Sprinkle steaks with salt and let sit at room temperature for 20-30 minutes
Crush black peppercorns in pepper or spice grinder. Spread evenly on a plate.
Press both sides of steak into peppercorns, making sure they stick.
In a cast iron or other heavy pan, melt butter and olive oil. When hot, add steaks. Cook for 4-5 minutes on each side, or more depending on thickness.
Remove steaks from pan. Pour off any excess fat.
With the pan off the heat, add cognac. Carefully light the contents of the pan on fire, then shake gently until flames die.
Add heavy cream, chicken broth, and Dijon and stir to combine. Bring mixture to a boil, then let reduce and thicken for 5-6 minutes, stirring frequently. Salt to taste.
Add steaks back to pan and spoon with sauce.
While steaks are cooking, boil water with 1 tsp salt. Add asparagus and cook for 4 minutes, until bright green and done. Serve with steaks.