hot sausage & shrimp mushrooms

So when I first created this recipe, I did it with Portobello's. But, there are a lot of people who don't enjoy that mushroom, and will eat a regular cap mushroom. So! I changed up some measurements so this will fit with a large pack of large white mushrooms.

Ingredients:
About 15 large sized button mushrooms
1/3 cup diced bellpepper
1/3 cup diced celery
1/3 diced onion
2 links hot sausage
1 cup peeled, deveined, chopped shrimp
1 tsp slap ya mama 
Splash of heavy whipping cream  (about 2 tbsp.)
1/3 cup parmesan
1/4 cup cut green onions