Preheat the oven to 375°F.

Line a square baking dish with aluminum foil and spray with nonstick cooking spray. Set aside.

Remove the stems from the mushrooms and discard, or save for another use.

Arrange the mushrooms in the baking dish with the cavities facing up. Set aside.

Place the cream cheese, Parmesan, panko, parsley, thyme, salt, and black pepper in a large mixing bowl. Set aside.

Finely dice the shallot.

In a large sauté pan over medium-high heat, cook the shallot and sausage, breaking the sausage up with a spatula as it cooks, until sausage is browned and shallot is softened, 5-6 minutes.

Add the cooked sausage and shallots to the panko and cheese mixture. Allow to cool for 2-3 minutes.

Using a rubber spatula or clean hands, mix all the ingredients together until thoroughly combined.

With a small spoon and clean hands, stuff a generous tablespoon of filling into each mushroom. Use enough so that the mushrooms are tightly packed and domed with stuffing.

Bake the mushrooms on middle rack of oven until stuffing is bubbling and golden brown, 20-23 minutes.

Check to see that mushrooms are done. Remove from oven or add time as needed.

Allow the mushrooms to cool for 5-10 minutes before serving. Refrigerate leftovers for up to 2 days.