Pat tenderloins dry with a paper towel. The more dry the outside of the meat is, the better crust you'll get while cooking.
30 minutes before cooking, season the steaks liberally with salt and pepper. Let the tenderloins sit at room temperature for 30 minutes before cooking.
Heat cast iron skillet over medium-high heat. Add lard and swirl to coat the pan.
Place tenderloins in the hot cast iron pan. Cook for 2-3 minutes per side or until internal temperature reaches 120-125°F for medium-rare. Tenderloins usually have 3(ish) sides. Don't forget to sear the third side!
After searing the 3 major sides, you can do a quick 10-15 second sear on any small sides that look raw on the outside.
Remove tenderloins to a cutting board and let rest for 10 minutes.
Slice or cut into medallions (about 1-1 ½" thick).
Sprinkle with flaked sea salt, if desired. Serve and enjoy!
