Place the chicken breasts, cubed butter, cream cheese, minced garlic cloves, salt, pepper, chicken broth, and heavy whipping cream into the slow cooker. Stir to distribute the ingredients evenly. Set the slow cooker to high for 2-3 hours or low for 4-5 hours, and cook until the chicken is thoroughly cooked and the mixture is creamy.

Once the chicken is fully cooked, remove it from the slow cooker and shred it using two forks. Return the shredded chicken to the crockpot, then add the cooked penne pasta and freshly grated parmesan cheese. Stir to combine everything well. Continue to cook on high for about 35-40 minutes, until the dish is hot and the pasta has absorbed some of the sauce. I like to reserve a little extra parmesan to sprinkle on top just before serving.

After the final cooking time, give the pasta a gentle stir to ensure everything is evenly coated. Serve hot, topped with extra freshly grated parmesan. You can also add a sprinkle of chopped fresh greens like parsley or basil for a pop of color and flavor.