These are a delicious addition to any party you are throwing. I always like to have several different types of appetizers set out for my guests. I’m not one to make the usual items that almost every party has. Offering guests a variety of interesting flavors makes for a great start to a gathering. 
These mushrooms are easy to put together and the stuffing can be made a couple of days ahead. The day of you can assemble, heat, and serve. 
Yield 24 mushrooms
24 crimini mushrooms, remove the stems, chop them finely, and clean the caps
2 Tbsp olive oil
½ onion, finely chopped
1 lb. ground Italian sausage 
⅓ cup gluten-free Panko breadcrumbs 
¼ cup fresh parsley
2 Tbsp fresh basil
¼ cup sundried tomatoes, finely chopped
¼ tsp salt
⅛ tsp pepper
4 Tbsp parmesan cheese, finely grated
Preheat oven to 400℉
In a large skillet on medium-high heat, add 2 Tbsp olive oil, sausage, the chopped stems, and the onion. Sauté until the sausage is cooked through and the onion and stems are starting to brown lightly. Pour out any grease that is in the skillet. 
Next, add to the skillet the breadcrumbs, parsley, basil, sun-dried tomatoes, salt and pepper, 3 Tbsp parmesan cheese, and stir together until thoroughly combined. 
Place the mushrooms on a large baking sheet. Fill all the caps with a heaping amount of stuffing. Sprinkle the remaining parmesan on top and place them in the oven for 12-15 minutes. The tops should be lightly brown on top. Using tongs, place the mushrooms on a platter, and serve immediately. 
Just Salt It, and enjoy!