Slow Cooker Mashed Potatoes

Ingredients

3 pounds Yukon Gold or Red potatoes, roughly chopped into 1-inch pieces and peeled if desired (*edited: Russett potatoes tend to oxidize more quickly and turn a bit gray while cooking, so I don't recommend them)
1 cup chicken or vegetable stock
1/4 cup butter, cut into small cubes
3 cloves garlic, minced
1/2 cup plain Greek yogurt or sour cream
1/2 teaspoon salt
1/4 teaspoon black pepper
1/3 - 1/2 cup milk, warmed
(optional add-ins: crumbled bacon bits, shredded cheddar cheese, crumbled blue cheese, chopped green onions or chives, etc.)

Instructions

Add potatoes and stock to the bowl of a slow cooker, and place butter cubes and minced garlic on top. Cover and cook on high for 3-4 hours, or on low for 7-8 hours, or until the potatoes are cooked and soft.
Use a potato masher or an electric mixer to mash the potatoes to your desired consistency. Stir in the Greek yogurt (or sour cream), salt, and black pepper. And add your desired amount of warm milk, until the potatoes reach your desired level of creamy-ness. Stir in any other add-ins if desired.
Serve warm.