These Slow Cooker Au Gratin Potatoes are the best side dish when you need to save oven space, especially for big holiday dinners like Thanksgiving, Christmas, or Easter!
Thinly sliced russet potatoes are layered with a cheesy roux and topped with more shredded cheese for a creamy, hearty side dish. The best part is that it’s hands-off once it’s in the crockpot so you can focus on enjoying the holiday or making other dishes for the big day.
Why You’ll Love This Recipe
- Frees up your oven. Now you can use your oven for rolls, turkey, ham or stuffing!
- Feeds a crowd. This recipe makes a giant batch that’s perfect for a big group.
- Perfect for a holiday spread. These potatoes pair perfectly with turkey, ham, or a big roast.
- Simple ingredients. Besides taking the time to shred your own cheese, there’s no specialty ingredients needed for this recipe.
Ingredients You’ll Need
Here’s what goes into these creamy slow cooker potatoes and some notes to help you get this recipe just right. Exact amounts are in the recipe card at the bottom of the post.
- Potatoes. We prefer using russet potatoes when cooking using this method because they tend to be a little softer. You could also use Yukon Gold, but they may need to cook longer. If you don’t mind skins, you can leave them on, but with our kiddos, we prefer to peel the potatoes first. Make sure they are thin enough (about ⅛” thick) or they won’t cook all the way through in the time suggested.
- Butter & Flour. You need these to make the roux for the cheese sauce. We use unsalted butter and all-purpose flour.
- Seasoning. We use garlic powder, onion powder, salt, and pepper for this recipe. You can play with the amounts to season to your liking, or add in different seasonings for different flavor profiles for your potatoes!
- Half and half: This is added to the roux for a very creamy sauce. You can use heavy cream for a thicker sauce or milk for a thinner sauce if you prefer.
- Sharp cheddar cheese: use freshly shredded cheese! Pre-shredded cheese has a coating that makes a creamy-lump free cheese sauce much harder to achieve. You’ll divide the cheese for the sauce, as well as the final topping at the end.
- Parmesan cheese: again, use freshly shredded cheese for the creamiest results. This adds a bit of a sharper flavor to the cheese, similar to authentic au gratin potatoes, which use Gruyere cheese.
- Fresh Parsley: we like to chop this and add it to the top before serving. It’s optional, but we like the flavor and pop of color it adds!
How to Make Slow Cooker Au Gratin Potatoes
- Prep your potatoes. Peel and slice potatoes. They’ll need to be about ⅛” thick. The easiest way to do this is with a mandolin. It will take a lot longer to individually slice each one. If you have a larger cheese grater with multiple sides, it may have a mandolin side like this one. Set the potatoes aside.
- Prep the cheese sauce. Make a roux by melting butter in a saucepan over medium heat. Whisk in flour until it’s smooth, then add in garlic powder, onion powder, salt, pepper, and half and half. Continue whisking until the sauce starts to thicken. This will take 3-4 minutes. Remove from heat and stir in 1 ½ cups sharp cheddar cheese and ½ cup Parmesan cheese.
- Layer the potatoes. Spray the inside of a 6-quart crockpot with nonstick cooking spray (don’t skip this part!). Layer ⅓ of the potatoes in the bottom of the pan. Add ⅓ of the cheese mixture, then repeat layers two more times. Cook on low for 5-6 hours, until potatoes are tender.
- Finish the dish. During the last 30 minutes of cooking, add the remaining ½ cup shredded sharp cheddar cheese on top, leaving off the lid to let some of the liquid evaporate. Serve warm, topped with fresh parsley.
Tip: If you want a crispy, golden brown cheese top like oven-made au gratin potatoes have, you’ll need to transfer the potatoes to an oven-safe dish and finish off with a broil, or use a slow cooker that can transfer directly to the oven like this one.
Variations to Try
- Switch up the cheese. Swap out the cheese for Gruyere, which is a classic way to make Au Gratin Potatoes.
- Make it in the oven. If you really want to make these in the oven, check out this oven-ready scalloped potato recipe.
- Add different toppings. We love throwing in bacon bits or topping it with chives for a bit of a different flavor.
Tips for the perfect scalloped potatoes
- Slice the potatoes as evenly as possible. The more evenly the potatoes are sliced, the more evenly they will cook.
- Grease your slow cooker. With the creamy sauce cooking for that many hours, you’ll want to grease your slow cooker to make sure it doesn’t stick too much.
- Keep the lid closed until the end. The more you open the lid, the longer it will take for the potatoes to get tender. Leave it on until the end of the cooking time, when you add the extra cheese and let some of the moisture burn off.
- Let them rest before serving. There will be moisture in the bottom from the potatoes, so we take the lid off the last 30 minutes or so before serving to help it thicken up.
- Don’t overcook the potatoes. You can leave them on warm for about 30 minutes or so after they are fork-tender, but much longer than that and the potatoes will start to get mushy.
Troubleshooting tips for Au Gratin Potatoes
Your potatoes may still be hard because the slices are too thick, the temperature of your slow cooker is generally lower, the slow cooker is too full, or the lid was opened a few times. You can continue cooking the potatoes in 30-minute increments to try and get them to soften up.
The sauce will actually look watery immediately after cooking. It continues to thicken up as it “rests”, with the lid off the slow cooker. That will usually thicken it up quickly!
Slow Cooker Cheesy Potatoes don’t have the same top as oven-made au gratin potatoes. If you like that flavor and texture, you’ll need to transfer the potatoes to an oven-safe dish and finish it off in the oven with a broil, or use a slow cooker that can transfer directly to the oven.
This recipe is written for a full batch in a 6-quart slow cooker, and it will fill it. It should not be doubled in a 6-quart, and it may be too much to double in an 8-quart, so you would need a significantly bigger slow cooker to be able to double the recipe successfully.
Make-Ahead and Storage Tips
This recipe is meant to be made day of, because the cheese sauce can start to separate or become too textured when made in advance and sliced potatoes can start to turn brown. The good news is that they do take 5-6 hours to cook, so you will have time to work on other recipes while they cook.
We would not recommend freezing this recipe, as the roux tends to separate and create a much more textured sauce.
To store, let the potatoes cool and transfer to an airtight container in the fridge for up to 4 days. Reheat slowly in a pot on the stovetop or in small batches in the microwave.
What to serve with Au Gratin Potatoes
This recipe is meant to be served with holiday dinner like Turkey, Ham, or a Beef Roast. It also goes great with a Sunday dinner like pork chops, pot roast, or baked chicken.
More sides to bring to your holiday dinner:
Here are some of our favorite sides that pair well with scalloped potatoes:
Frequently Asked Questions
We’ve found that Russet potatoes will give you the tender texture most consistently in the slow cooker.
No! If you don’t mind potatoes with the peel on, or like them better that way, feel free to leave the peels on (just make sure they’re washed and dried well before slicing).
We recommend slicing them about ⅛” thick to be able to cook completely in 5-6 hours on low.
Yes! These will cook in about 2-3 hours on high, but they may end up overcooking, depending on how hot your slow cooker runs, so watch them closely!
We wouldn’t recommend this. These are best made day of, but cooking them on the low setting will give you 5-6 hours of time to work on other recipes.
Slow Cooker Au Gratin Potatoes Recipe
Ingredients
- 3 lbs russet potatoes, peeled and cut into ⅛” thin slices
- ¼ cup butter
- ¼ cup all-purpose flour
- 1 teaspoon garlic powder
- 1 teaspoon onion powder
- ½ teaspoon salt
- ½ teaspoon black pepper
- 2 cups half and half
- 2 cups freshly shredded sharp cheddar cheese, divided
- ½ cup freshly shredded Parmesan cheese
- Fresh parsley, for topping
Equipment
- Mandolin Slicer, or sharp knife
Instructions
- Peel and slice potatoes, then set aside. (I used a mandolin to make the slices quickly and evenly).
- In a saucepan over medium heat, melt butter. Whisk in flour until it makes a smooth, thick roux. Add in garlic powder, onion powder, salt, pepper, and half and half. Continue whisking until the sauce starts to thicken (3-4 minutes).
- Remove from heat and stir in 1 ½ cups sharp cheddar cheese and ½ cup Parmesan cheese.
- Spray the inside of your crockpot (we used a 6-quart) with nonstick cooking spray. Layer ⅓ of the potatoes in the bottom of the pan. Add ⅓ of the cheese mixture, then repeat layers two more times.
- Cook on low for 5-6 hours, until potatoes are tender.
- During the last 30 minutes of cooking, add the remaining ½ cup shredded sharp cheddar cheese on top, leaving off the lid to let some of the liquid evaporate. Serve warm, topped with fresh parsley.
Notes
Nutrition
Did You Make This Recipe?We’d love to hear your thoughts! Leave a review or a question in the comment section below the post.
