Place the chicken breasts in the bottom of the slow cooker.

Add the diced onion, minced garlic, chicken broth, paprika, dried parsley, salt, and black pepper to the slow cooker.

If using, add the sliced mushrooms on top of the chicken mixture.

Cover and cook on low for 6-7 hours or on high for 3-4 hours, until the chicken is fully cooked and tender.

Once the chicken is cooked, remove it from the slow cooker and shred it into bite-sized pieces using two forks.

Add the cream cheese and cream of mushroom soup to the slow cooker, stirring until fully combined and smooth.

Return the shredded chicken to the slow cooker, stirring to coat it in the creamy sauce. Allow it to heat through for about 15-20 minutes.

While the sauce is warming, cook the egg noodles according to the package instructions, then drain and toss with olive oil or butter to prevent sticking.

Serve the chicken stroganoff over the egg noodles, and garnish with freshly chopped parsley if desired.