Preheat the oven to 375 degrees F (190 degrees C). Line a baking sheet with foil.
Bring a large pot of water to a rolling boil. Drop peppers into the boiling water. Turn off the heat and let peppers soak until softened a bit, about 5 minutes. Remove peppers and set aside until cool enough to handle.
While the peppers are cooling, mix sausage and cream cheese thoroughly in a bowl.
Fill peppers with sausage mixture and place onto the prepared baking sheet. Roll any extra sausage mixture into meatballs and place alongside the stuffed peppers. Spoon pasta sauce over peppers and meatballs and sprinkle with Parmesan cheese.
Bake in the preheated oven until sausage mixture starts to turn golden brown and an instant-read thermometer inserted into the center reads at least 160 degrees F (71 degrees C), about 35 minutes.