For the mushrooms
01 -
20 medium cremini mushrooms, about 1 1/2 to 2 inches wide
02 -
1 tablespoon olive oil, plus more for the baking sheet
03 -
1/4 teaspoon kosher salt
For the beef filling
04 -
8 oz (225 g) lean ground beef
05 -
1/4 cup finely diced yellow onion
06 -
3/4 cup finely chopped mushroom stems
07 -
2 cloves garlic, minced
08 -
1/2 teaspoon Italian seasoning
09 -
1/2 teaspoon kosher salt
10 -
1/4 teaspoon black pepper
11 -
2 oz (55 g) cream cheese, softened
12 -
1/3 cup (25 g) panko breadcrumbs
13 -
1/4 cup (25 g) grated Parmesan cheese
14 -
2 tablespoons chopped fresh parsley, plus more for serving
For the topping
15 -
1/2 cup (55 g) shredded mozzarella cheese