Meanwhile place a saucepot over medium heat add butter. Swirl pan to coat bottom. Sauté garlic for 1 minute, until fragrant (being careful not to burn). Add mushrooms and cook for 8-10 minutes.
Add heavy cream and bring to a simmer, reduce heat to medium low. Once mixture has reduced, season with salt and pepper to taste.
In a bowl mix Mini Manicotti with sauce and chicken. Place in a 13" x 9" baking dish. Sprinkle with Parmesan.
Cover with aluminum foil and bake in oven for 35 minutes.
Remove foil and cook for an additional 5 minutes, or until top turns slightly brown.
Remove from oven and let rest for 3-5 minutes. Sprinkle with parsley before serving.