In a 4 quart (or larger) crock pot, place frozen chicken breasts into the bottom. Pour one cup of chicken broth over top.
Season with 1 teaspoon of Italian seasoning and a dash of salt and pepper.
Cover and cook on high for 3 hours (or low for at least 6 hours).
Drain excess broth and fat from cooked chicken. In a bowl, combine softened butter, mayonnaise, Parmesan cheese, minced garlic, 1 teaspoon Italian seasoning and a dash of salt and pepper. Stir to combine.
Scoop this mixture on top of cooked chicken.
Cover and cook on high for an additional 30 minutes until sauce is creamy and cheese is melted.