Pat the sirloin steak 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 skillet, grill, or cast-iron pan over high heat
Add a small amount of oil with a high smoke point
Place the steak in the hot pan or on the grill
Sear for 3 to 5 minutes per side, depending on thickness and desired doneness
Sear the edges briefly if needed
Reduce heat if necessary and continue cooking to preferred doneness
Use a meat thermometer if desired
Remove the steak from heat when it reaches the target temperature
Add butter, garlic, or herbs during the last minute if desired
Rest the steak for 5 to 10 minutes before slicing
Slice against the grain
Serve immediately