In a small bowl, combine together the cornstarch, salt, pepper, garlic, Italian seasoning, parsley, and chicken stock. Pour on top of the chicken. This can also be prepared the night before.
Spread the sundried tomatoes on top and cover the pot with the lid. Set the crockpot on low for 6-8 hours or high for 4 hours.
The last 45 minutes-1 hour of cooking, stir in the tortellini, heavy cream, and parmesan cheese.