Preheat the oven to 350 degrees F. Prep a medium baking sheet by spraying it lightly with cooking oil or lining it with parchment paper. If you have one, I suggest placing a baking rack on the baking sheet so that the excess moisture can drop off of the mushrooms as they cook. But this is not totally necessary. 

Prep the mushrooms by wiping them gently with a damp paper towel. You do not want to rinse them in the sink because the mushrooms will absorb too much of the water and be soggy when cooked. Remove the stems from the mushrooms so that you have a nice cavity inside of each. I like to do this by simply putting my thumb on the base of the stem and then pushing it away from the mushroom which will cause it to very easily and cleanly snap off from the mushroom. Place the mushroom caps on the prepared baking sheet/rack.

Discard half of the mushroom stems (you can freeze them for later use as desired). Chop the remaining mushroom stems up so that they’re finely diced.

Heat the butter in a large skillet over medium heat. Once hot, add in the mushroom stems, garlic, and shallot. until the liquid has cooked out of the mushrooms, about 8-10 minutes. Stir often to avoid burning the garlic. Remove from the heat.

Add in the cream cheese, salt and pepper, and parsley. Stir to combine with the mushrooms mixture until fully mixed together. Stuff the mushroom caps evenly with the cream cheese mixture so that it’s lightly mounded.

In a small bowl, mix together the parmesan and breadcrumbs. Sprinkle the breadcrumb mixture evenly over the top of the mushrooms.

Bake for 20-25 minutes until the mushrooms are hot, the cheese is lightly bubbling, and the tops of the mushrooms are golden brown. Let cool slightly and enjoy!