Place aluminum foil on a baking sheet and spray with non-stick cooking spray.
While oven preheats, remove the stems of the mushrooms and wipe with a wet cloth to remove excess dirt. Place the mushrooms on the baking sheet.
Begin stuffing each mushroom with cooked stuffing mix. Divide the stuffing mix evenly.
Cut two tablespoons of butter and then cut into fours, so that you have 8 cubed pieces of butter. Place a single piece of butter on top of each stuffed mushroom.
Bake for 10 minutes. Then remove from the oven and divide the shredded monterey jack cheese between the 8 mushrooms. Bake for an additional 5 minutes. Remove from the oven and serve immediately.
Notes
You can easily make this with gluten-free stuffing to fit into your diet.