Bring the porterhouse steak to room temperature for 30–45 minutes
Pat the steak dry with paper towels
Season both sides generously with salt and black pepper
Preheat a cast-iron skillet, grill, or broiler to high heat
Add a small amount of high-smoke-point oil if using a skillet
Sear the steak for 2–4 minutes per side
Sear the fat edge and sides briefly
Reduce heat or move to indirect heat if needed
Cook until the desired internal temperature is reached
Use a meat thermometer for accuracy
Remove the steak from heat
Rest the steak for 5–10 minutes
Slice against the grain
Serve immediately