- 4 cups chicken stock, or as needed
- 3 skinless, boneless chicken breasts
- 1 (8 ounce) package manicotti shells
- 3 cups shredded mozzarella cheese, divided
- 1 (8 ounce) package cream cheese, softened
- 1 (8 ounce) package fresh mushrooms, finely chopped
- 1/4 cup chopped green onions (optional)
- 3 cloves garlic, minced
- 2 (16 ounce) jars Alfredo sauce
- Bring chicken stock to a boil in a saucepan. Add chicken breasts. Cook until chicken can be easily pulled apart with a fork, about 30 minutes. Drain and cool until easily handled. Shred using 2 forks.
- Preheat oven to 375 degrees F (190 degrees C).
- Bring a large pot of lightly salted water to a boil. Cook manicotti in the boiling water, stirring occasionally, until still firm to the bite, about 7 minutes. Drain.
- Mix shredded chicken, 2 cups mozzarella cheese, cream cheese, mushrooms, green onions, and garlic together in a bowl. Pour in enough Alfredo sauce until filling has a thick and creamy consistency.
- Spoon chicken filling into a piping bag, reserving about 1/2 cup of the filling in the bowl. Pipe filling into manicotti.
- Mix remaining Alfredo sauce with reserved chicken filling in the bowl.
- Arrange stuffed manicotti in a baking dish. Cover evenly with Alfredo sauce mixture until there are no dry spots. Sprinkle remaining 1 cup mozzarella cheese on top. Cover baking dish with aluminum foil.
- Bake in the preheated oven until cheese is melted and sauce is bubbling, about 50 minutes. Remove aluminum foil and continue baking until cheese starts to brown, about 10 minutes.