Sprinkle salt in a large cast-iron skillet over medium-high heat.
Add steaks; saut 2 minutes on each side.
Remove from pan.
Add garlic; saut 30 seconds.
Add sherry; boil 30 seconds, scraping skillet to loosen browned bits. Return steaks to pan; cook 2 minutes.
Add soy sauce and pepper.
Remove steaks to serving plates.
Remove pan from heat; stir butter into sherry mixture until blended. Divide sauce evenly over steaks. Top each steak with 3/4 teaspoon ginger, if desired.