Preheat oven to 375 degrees F (175 degrees C). Spray a baking sheet with cooking spray. Clean mushrooms with a damp paper towel. Carefully break off stems. Chop stems extremely fine, discarding tough ends .
Place In the oven for 12-15 minutes or until golden brown and hot liquid appears
For melted cheese: fillthe mushrooms cups with shredded cheese and back in the oven for a minute (until well melted)
Fill the rest of the mushrooms cups with tahini dressing