The night before, prepare steak by patting dry and salting all sides to taste. Place on wired rack, uncovered, in the fridge over night.
To cook, preheat cast iron skillet to med-high. Generously coat the outside of steak with preferred vegetable oil.
Once cast iron is hot, add steak to pan, cooking 3 minuted per side. Use a timer and rotate cooking on all sides.
Remove steak and cover with foil.
While your steak rests, prepare the sauce
Turn off the heat for the skillet. Using several wet paper towels, wipe out extra oil and any burnt bits left behind, but do not wash out the skillet.
Turn heat back on and add cognac.
After 30-60 seconds, add beef stock.
Reduce heat and cook on med for 5-7 minutes.
Add cream and freshly cracked black pepper.
Cook on med-low stirring occasionally. The sauce will reduce and thicken. (it will continue to thicken as it cools off, so cook it down a little thinner than you really want, otherwise it will be too thick)
Give it a QC check for flavor and add salt or pepper as needed.
When your'e happy with the flavor, pour sauce into individual serving cups or sauce pitcher.
Slice steak and get yourself a happy beverage.