Add in seasoning and place spoonfuls of cream cheese on top of warm sausage.
Stir cream cheese into sausage so it melts and totally incorporates.
Place mushrooms cap side down on a baking sheet, close together.
Spoon sausage mixture into each mushroom - about 1 - 1 1/2 Tbsp.
Bake in a 350 degrees F oven for 20-25 minutes.
Remove from baking sheet immediately to serving plate.
Notes
There will be liquid on the baking sheet while they bake. Mushrooms hold a lot of liquid that releases as they bake. It is totally normal. Remove them from the baking sheet to a serving plate immediately so they don't sit in the liquid.
If you like, you can place some kind of oven safe baking rack on the baking sheet to place the mushrooms on so they don't sit in the liquid.
Leftovers: You can store any leftover cooked stuffed mushrooms in an air-tight container, in the fridge for 3-5 days. To reheat, you can use a microwave to reheat the mushrooms for a few seconds, in the oven covered with foil at 250 degrees F or in an air fryer. They are best enjoyed the first day.