Lightly grease a large skillet or grill pan and warm over medium heat. Add the sliced zucchini, carrots and mushrooms. Cook on each side for about 3-5 minutes, until light golden brown and tender, but still slightly crisp. Remove from heat and set aside.
Spread butter or olive oil on one side of each slice of bread. On the opposite side of each piece, spread the tahini on top. Layer with baby spinach and grilled vegetables then press the two slices together (butter side facing out). Grill (or cook in the skillet) over medium-low heat until light golden brown on each side. Slice then serve warm and enjoy!
Nutrition information is an estimate and will vary based on the brand of bread you used.