Step 1

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 until the potatoes are cooked and soft.

Step 2

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.

Step 3

Serve warm.