Start by browning your ground Italian sausage in a skillet over medium heat. Break it up as it cooks until no pink remains. Drain off any excess grease and set it aside.
In a large bowl, combine the cream cheese, sour cream, cottage cheese, one cup of the shredded mozzarella, Italian seasoning, garlic powder, onion powder, and a pinch of salt and pepper. Stir until smooth and well blended. This is your creamy layer and it should look thick and spreadable.
Spray your slow cooker with non stick spray. This helps prevent sticking and makes cleanup easier later.
Spread a thin layer of marinara sauce across the bottom of the slow cooker. This keeps the tortellini from sticking and helps everything cook evenly.
Add half of the uncooked tortellini in an even layer. Try to spread them out so they cook evenly.
Spoon half of the creamy cheese mixture over the tortellini and gently spread it out. No need to be perfect.
Add half of the browned sausage over the cheese layer. Then pour half of the remaining marinara sauce over the top.
Repeat the layers with the remaining tortellini, creamy cheese mixture, sausage, and marinara sauce.
Sprinkle the remaining mozzarella cheese and all of the Parmesan cheese evenly over the top.
Cover and cook on low for 4 to 5 hours until the tortellini are tender and the sauce is hot and bubbly.
Before serving, sprinkle with chopped parsley and basil if desired.