Slow Cooker Au Gratin Potatoes: Creamy, Cheesy and Easy
For slow cooker au gratin potatoes, layer about 3 lb of thinly sliced potatoes with onion, a quick cheese sauce and shredded cheddar. Cook on LOW for 5 to 6 hours or HIGH for about 3 to 4 hours, until a knife slides through easily.
Make the sauce with flour so it stays creamy, add most of the cheese at the end, and finish under the broiler if you want a golden top.
- Slice potatoes ⅛ inch thick so they cook evenly. A mandoline makes this easy.
- Yukon Gold potatoes hold their shape; russets make a softer, starchier gratin.
- A flour-thickened sauce stops the milk from separating during long cooking.
- Lay a paper towel under the lid to catch condensation and stop a watery top.
- Refrigerate leftovers within 2 hours and eat within 3 to 4 days.
Slow cooker au gratin potatoes recipe
Ingredients
- 3 lb Yukon Gold or russet potatoes, peeled and sliced ⅛ inch thick
- 1 small onion, thinly sliced
- 3 tbsp butter and 3 tbsp all-purpose flour
- 2 cups whole milk (or 1½ cups milk plus ½ cup cream)
- 1 tsp salt, ½ tsp pepper, ½ tsp garlic powder, pinch of nutmeg
- 2 cups shredded sharp cheddar, divided (or half Gruyère)
- Chopped chives to serve
Steps
- Grease the crock. Butter the inside of a 5 to 6-quart slow cooker well.
- Make the sauce. Melt the butter in a pan, whisk in the flour for 1 minute, then slowly whisk in the milk. Simmer until thickened. Season and stir in ½ cup of the cheese.
- Layer. Layer a third of the potatoes and onion, then a third of the sauce. Repeat twice, ending with sauce.
- Cover with a towel. Lay a clean paper towel over the crock, then put the lid on. It catches drips that would make the top watery.
- Cook. Cook on LOW for 5 to 6 hours or HIGH for 3 to 4 hours, until a knife slides through the center.
- Add the cheese. Sprinkle the remaining cheese on top, cover and cook 15 minutes more until melted.
- Brown (optional). If your crock is oven-safe, broil it for 3 to 5 minutes. Otherwise, serve as is.
Plain milk can separate and look curdled after hours of heat. Cooking it into a flour-thickened sauce first keeps it smooth and creamy.
Best potatoes for au gratin
| Potato | Result |
|---|---|
| Yukon Gold | Creamy texture, slices hold their shape |
| Russet | Softer, more starchy, thickens the sauce |
| Red potatoes | Firm; leave the skin on for color |
Variations
- With ham: layer 2 cups diced ham between the potatoes for a main dish.
- With smoked sausage: add sliced smoked sausage, as in many boxed au gratin recipes.
- From a box mix: use the box’s potatoes and sauce, add the liquid the package lists, and cook on LOW, checking from 3 hours.
- Lighter version: use milk and stir in some plain Greek yogurt at the end, off the heat, for tang.
Food safety and storage
USDA FSIS advises refrigerating leftovers within 2 hours and eating them within 3 to 4 days. It also says not to reheat leftovers in a slow cooker. Reheat portions in the oven or microwave until hot all the way through.
Frequently asked questions
How long do au gratin potatoes take in a slow cooker?
About 5 to 6 hours on LOW or 3 to 4 hours on HIGH, until the potatoes are tender in the center.
Do I need to precook the potatoes?
No. Thin slices cook through in the sauce. Thick slices may stay firm, so keep them about ⅛ inch.
Why are my slow cooker au gratin potatoes watery?
Condensation drips from the lid. Lay a paper towel under the lid, and use a flour-thickened sauce.
Can I make them ahead?
Yes. Cook, cool quickly, refrigerate, then reheat in the oven at 350°F until hot. Do not reheat in the slow cooker.
The bottom line
Slice potatoes thin, layer them with a creamy cheese sauce, and cook low and slow. Add the last of the cheese at the end, and you have an easy, hands-off side for holidays and potlucks.
- USDA Food Safety and Inspection Service, Slow Cookers and Food Safety.
- USDA Food Safety and Inspection Service, Leftovers and Food Safety.
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