Step 1

In a small bowl, whisk together olive oil, balsamic vinegar, and garlic.

Step 2

Place mushroom caps in a large, zipper seal plastic bag and add the olive oil marinade. Seal the bag and flip it over a few times to distribute the marinade over the mushrooms. Allow to rest for 15 minutes.

Step 3

Preheat the oven to 450ºF. Place marinated mushrooms stem side down on a rimmed baking sheet. Bake 10 minutes.

Step 4

Meanwhile, prepare the filling by combining spinach, 1/4 cup Parmesan cheese, and heavy cream in a medium bowl. Season to taste with salt and pepper.

Step 5

Remove the mushrooms from the oven and flip. Divide the spinach filling over the mushrooms, then top evenly with mozzarella cheese and remaining parmesan.

Step 6

Return the mushrooms to the oven for 10 minutes or until the cheese is melted and beginning to brown.

Step 7

Serve warm with mashed potatoes, grilled veggies, or your other favorite sides.