Tamari soy sauce is similar to regular soy sauce but is slightly thicker and has a richer flavor. It is available at most grocery stores. Besides being the perfect condiment for the tofu, this sauce makes a nice addition to the soba noodles -- just drizzle a little bit on top.
This recipe is also featured in "Martha Stewart's Dinner at Home."
It's a good idea to place the plastic bag holding the steak and marinade on a rimmed baking sheet or in a baking dish, in case of any leaks.
This recipe is one of our Better Basics: 10 New Takes on Family Favorites, see the others.