Slow Cooker Mashed Potatoes

• 5 lb baking potatoes, peeled, cut into 1-inch chunks
• 1 1/2 cups chicken broth
• 1/4 cup butter, cut into chunks
• 1 cup sour cream 
• 1 teaspoon salt
• 1/4 teaspoon ground black pepper, if desired 
• 1/2 to 1 cup milk, warmed

1. In 4- to 5-quart slow cooker, place potatoes, chicken broth and butter.
2. Cover; cook on High heat setting 4 hours to 4 hours 30 minutes or until potatoes are tender.
3. Add remaining ingredients except milk. Mash potatoes using potato masher, or beat with electric mixer on low speed until well blended. Do not overmix. Stir in enough milk for desired creamy consistency.
4. Cover and keep warm on low or warm heat setting until serving time, up to 2 hours. Stir before serving and you may need to mix in additional milk if potatoes have stiffened while on the warm or low setting.