By Brigit Binns
Flavor the mayonnaise
In a small bowl, stir together the mayonnaise and horseradish. Spread the mayonnaise mixture generously on each slice of bread.
Assemble the sandwiches
Thinly slice the steak across the grain. Divide the steak, tomatoes, and lettuce among 4 of the bread slices, top with the remaining slices, and serve