In a bowl combine the steak, soy sauce, olive oil
, garlic, and pepper. Let marinate 15 minutes. Warm a nonstick skillet over moderately high heat until it is hot. Add the steak, marinade
, and salt, and cook, stirring, just until the meat is no longer pink (be careful not to overcook). With a slotted spoon transfer the steak to a plate. Add the remaining oil to the skillet and warm it over moderately high heat until hot. Add the mushrooms and salt and pepper, and cook, stirring, for 5 minutes.
In a salad bowl combine the steak, mushrooms
along with any pan juices, and spinach leaves, tossing gently to combine.
For the dressing
: In a bowl whisk together the vinegar, mustard, lemon
pepper, and salt to taste. Add the oil, in a stream, whisking until combined well. Whisk
in the herbs
. Pour the dressing over the salad and toss to combine. Serve with grilled or toasted bread.