Based on https://www.allrecipes.com/recipe/15184/mouth-watering-stuffed-mushrooms/
24 oz mushrooms
1 tbsp oil
1 tbsp minced garlic (from a fridge jar)
1 package cream cheese (8 oz), softened
1/4 cup shredded Parmesan cheese (maybe also a bit of the powdery Parmesan cheese for texture)
1/4 tsp black pepper
1/4 tsp onion powder
Scant 1/4 tsp ground cayenne pepper
Maybe add 1/4 cup bread crumbs next time
3 tbsp butter (optional)
Clean mushrooms; separate steps and caps, lay caps out to dry, mince/chop stems. Sauté oil, minced stems, and garlic until stems stop releasing liquid and start to brown. Put into a small bowl to cool. Put butter into still-warm pan to melt. Mash everything else together (cream cheese through cayenne/bread crumbs). Once mushroom stems have cooked, mix them in as well. Spray baking sheet, lay out mushroom caps, fill with filling. Optionally sprinkle with more bread crumbs. Brush mushrooms with melted butter to keep from drying out (optional — it does help, but they’re still good without it). Bake at 350 for 20 minutes, until mushrooms are tender and tops are golden.