Heat the butter in a large skillet over medium-high.
When the butter has completely melted add the swordfish.
Let cook for 4-5 minutes until a nice black crust forms. Flip. Cook on the second side. Swordfish should be cooked until 145 on an internal thermometer.
Notes
Spice Level: This has some kick. If you want milder fish cut the amount of cayenne pepper back to ¼-1/2 teaspoon or omit it entirely.