Prep Ahead:
Peel potatoes and slice them into large chunks.
Lightly smash garlic cloves to break up the skin, which then gets discarded.
Combine the potatoes and garlic in a large resealable bag or container. If using a bag, press out as much air as you can to avoid any discoloring of the potatoes.
The chopped potatoes will last for about 2 days in the fridge. Some discoloration may occur, but will not affect the taste.
Prepare From Prepped:
Combine the chopped potatoes and garlic with butter, salt, and water to the slow cooker.
Cook according to the instructions in Steps 4-6
Make From Fresh:
Peel the potatoes and slice them into large chunks.
Lightly smash the garlic to break the papery outsides, then peel the cloves.
Add the potatoes, garlic, butter, salt, and water to a 4 or 6-quart slow cooker and secure the lid.
Cook on low for 3 hours.
When the potatoes are ready, remove the lid and add the milk.
Mash the potatoes until creamy and serve.