Preparation:

Marinate steak in olive oil and soy sauce for one hour in a ziplock bag. Once marinated, remove the steak from the bag and season with pepper (no need for salt because of the soy sauce). Grill at high heat for 15 minutes (or until desired doneness), flipping meat halfway through. While steak is cooking, combine horseradish, yogurt, and mayonnaise in a bowl and whisk to incorporate (depending on your tolerance, more or less horseradish may be used). Set sauce aside.

Slice tomato into ¼-inch slices. Wash lettuce leaves, pat dry, and set aside.

Multi-grain rolls may be toasted on the grill at this time. Remove steak from grill and let rest for 5 minutes.

To serve, slice the steak no more than ¼-inch thick, on the bias (angle) and against the grain of the meat. Place steak on bun with tomato slices and lettuce. Top with horseradish sauce.

(Note: A grill pan or plancha (flattop grill) may be substituted if a grill is not available.)