Pat the filet mignon dry with paper towels
Season both sides generously with salt and black pepper
Let the steak sit at room temperature for 20 to 30 minutes
Heat a heavy skillet over medium-high heat
Add a small amount of oil with a high smoke point
Place the steak in the hot skillet
Sear for 2 to 3 minutes without moving it
Flip the steak and sear the other side for 2 to 3 minutes
Sear the edges briefly with tongs
Add butter, garlic, and herbs if desired
Spoon the melted butter over the steak for 1 to 2 minutes
Check internal temperature with a meat thermometer
Cook to 125°F for rare, 130°F for medium-rare, or 140°F for medium
Remove the steak from the skillet
Rest the steak for 5 to 10 minutes
Slice and serve