Place garlic bread on a baking sheet, bake 3 to 4 minutes until bottom is just beginning to brown; turn to other side, leaving on baking sheet. Set aside. Meanwhile, squeeze some of the liquid out of the spinach, leaving it moist but not wet; place in a medium skillet over medium heat. Add mushrooms, onions and garlic & herb seasoning; cook and stir until mushrooms are just tender, 5 minutes.
Place 2 slices turkey on the toasted side of each slice of bread; top each with 1/4 cup spinach mixture, 1 tomato slice and 1 slice of cheese.
Return to oven, bake 5 minutes or until cheese is melted and spinach is heated through. Serve immediately.