Slow Cooker Garlic Butter Potatoes

3 tablespoons salted butter melted (plus a little extra for greasing the slow cooker)
2 pounds russet or Yukon Gold potatoes thinly sliced (about ⅛-inch thick)
2 large yellow onions thinly sliced (about ⅛–¼-inch thick)

Prep Slow Cooker: Lightly grease the inside of a 4- to 6-quart slow cooker with a bit of butter.
Prep Veggies: Slice the potatoes and onions into thin, even rounds (about ⅛-inch thick).
Butter Bottom: Drizzle 1 to 2 teaspoons of melted butter into the bottom of the slow cooker.
First Layer: Add a single, slightly overlapping layer of potato slices to the bottom. Sprinkle a loose handful of sliced onions over the potatoes.
Butter & Season: Drizzle a teaspoon of melted butter over this layer. (Add a tiny pinch of salt and pepper here if desired, though the salted butter is usually enough).
Repeat Layers: Repeat the layers of potatoes, onions, and melted butter until all ingredients are used. Finish with a final drizzle of butter on top.
Cook: Cover and cook on LOW for 6 to 7 hours, or on HIGH for 3 to 4 hours, until potatoes are tender.
Rest & Serve: Let rest with the lid off for 10 minutes to allow the juices to thicken. Scoop deep to get every layer, spooning the bottom juices over the top before serving.
Enjoy!