Slow Cooker Potato & Onion Bake (4 Ingredients)

This classic recipe proves that a few basic ingredients can create something truly delicious. Handed down through generations, it combines potatoes, onions, flour, and butter into a warm, hearty dish packed with comforting flavor. As it cooks slowly, the layers become tender and infused with rich buttery goodness, all with very little hands-on work.

Perfect for busy schedules or leisurely family meals, this slow cooker side dish requires minimal preparation and delivers satisfying results every time. It pairs beautifully with roasted meats, chops, sausages, or meatloaf. Add a fresh vegetable or salad and a tangy accompaniment like coleslaw or pickles for a well-balanced meal. Any leftovers can be reheated and even served alongside eggs the next day.

Ingredients

Ingredient	Quantity	Preparation
Unsalted butter	3 tablespoons	Plus extra for greasing
Russet or Yukon Gold potatoes	2½ pounds	Peeled and sliced ⅛ inch thick
Yellow onions	2 large	Thinly sliced
All-purpose flour	3 tablespoons
Kosher salt	1 teaspoon	Adjust to taste
Black pepper (optional)	½ teaspoon

Instructions

1. Prepare the Slow Cooker

Lightly coat the inside of a 4- to 6-quart slow cooker with butter to prevent sticking.

2. Slice the Vegetables

Cut the potatoes into thin, even rounds, approximately ⅛ inch thick. Thinly slice the onions into half-moon shapes.

3. Make the Seasoning Mixture

In a small bowl, combine the flour, salt, and black pepper, if using.

4. Build the Layers

Arrange a layer of potatoes across the bottom of the slow cooker, overlapping slightly. Add a layer of onions, then sprinkle a small amount of the flour mixture over the top. Scatter a few small pieces of butter across the layer.

Continue layering the potatoes, onions, flour mixture, and butter until all ingredients have been used. Finish with a final layer of potatoes and distribute the remaining butter over the top.

5. Cook

Cover with the lid and cook until the vegetables are tender:

• HIGH: 3½ to 4 hours
• LOW: 6 to 7 hours

The dish is ready when the potatoes are soft and the onions have become tender and flavorful.

6. Optional Finishing Step

For a slightly firmer texture and less moisture, leave the slow cooker on WARM or LOW for 15 to 20 minutes with the lid slightly ajar before serving.

7. Serve

Spoon through the layers to capture a mix of buttery potatoes and softened onions in each serving. Taste and adjust the seasoning if desired before bringing it to the table.