Place the boneless skinless chicken breasts in the bottom of a 6-quart slow cooker.
Pour the entire bottle of Olive Garden Italian Dressing over the chicken.
Sprinkle the grated Parmesan cheese and black pepper over the top.
Place the block of softened cream cheese on top of the chicken.
Cover the slow cooker with the lid.
Cook on High for 4 hours or on Low for 5 to 6 hours, until the chicken is cooked through and shreds easily.
About 20 minutes before serving, cook the penne pasta in a large pot of salted boiling water according to package directions until al dente.
Drain the pasta well.
Use two forks to shred the chicken directly in the slow cooker.
Whisk the shredded chicken and sauce together until the cream cheese is fully melted and incorporated into a creamy sauce.
Add the cooked, drained pasta to the slow cooker and toss until evenly coated.
Garnish with chopped fresh parsley and serve warm.