This is the scalloped potato casserole most people actually make: sliced potatoes layered in a dish, covered with condensed cream soup thinned with milk, and baked until the top browns and the potatoes are tender all the way through.
There is no roux to make and no sauce to whisk. The condensed soup provides the thickener, the salt, and the body in one step.
The one thing that decides whether it works is slice thickness, and the second is covering the dish for the first stretch of baking.
Why You Will Love This Recipe
Ten minutes of prep. Slice, layer, pour, bake.
No sauce to make. The condensed soup handles the thickening, which is where most scalloped potato recipes go wrong.
It feeds ten cheaply. Potatoes and a can of soup is one of the least expensive sides for a crowd.
It can be assembled ahead. Build it in the morning and bake it before dinner.
It reheats better than most potato dishes. The sauce keeps the layers moist.
Recipe Overview
Prep time: 15 minutes
Bake time: 75 to 90 minutes
Rest time: 15 minutes
Total time: About 2 hours
Yield: 10 servings
Difficulty: Easy
Best for: Holidays, Sunday dinner, potlucks, ham dinners, feeding a crowd
Ingredients
For the Potatoes
• 3 pounds (1.4 kg) russet or Yukon Gold potatoes
• 1 medium yellow onion, thinly sliced
• 1 teaspoon kosher salt
• 1/2 teaspoon black pepper
For the Sauce
• 2 cans (10.5 oz each) condensed cream of chicken or cream of mushroom soup
• 1 1/4 cups (300 ml) whole milk
• 3 tablespoons unsalted butter, melted
• 1 teaspoon garlic powder
• 1/2 teaspoon onion powder
• 1/2 teaspoon dried thyme
• 1/4 teaspoon ground nutmeg
• 1/2 teaspoon black pepper
For the Topping
• 1 1/2 cups (170 g) shredded sharp cheddar, optional
• 2 tablespoons chopped fresh parsley
Choosing the Right Potatoes and Soup
Russet potatoes are the traditional choice for scalloped potatoes. Their high starch content releases into the sauce and thickens it further, and they turn very soft and tender.
Yukon Gold potatoes hold their shape better and give more distinct layers. They are the better choice if you want to see the slices in the finished dish.
Red potatoes are too waxy. They stay firm and the layers never soften into one another.
Cream of chicken soup gives the most neutral, savoury result and is the most common choice.
Cream of mushroom adds more depth and works particularly well alongside beef.
Cream of celery is the mildest of the three and lets the potatoes lead.
Do not use two different soups without tasting. They vary considerably in salt content, and doubling up on a salty variety leaves the dish over-seasoned.
Why Slice Thickness Decides Everything
Almost every complaint about scalloped potatoes traces back to slices that were too thick.
Aim for about 1/8 inch. At that thickness the potatoes cook through in about ninety minutes and the layers soften into one another.
A quarter inch is too thick. Those slices need well over two hours and the top burns long before the centre is tender.
A mandoline is the easiest tool. Consistency matters more than speed, and a mandoline gives every slice the same cooking time.
Uneven slices cook unevenly. Thin slices turn to mush while thick ones stay firm in the same dish, which is why some people find raw pieces in an otherwise soft casserole.
Do not rinse the slices. The surface starch helps thicken the sauce. Rinsing washes it away.
How to Make Easy Scalloped Potatoes
Step 1: Prepare the dish
Preheat the oven to 350°F (175°C) and generously butter a 9×13 inch baking dish.
Step 2: Make the sauce
Whisk the condensed soup, milk, melted butter, garlic powder, onion powder, thyme, nutmeg, and black pepper together in a bowl until smooth.
Whisk it properly. Condensed soup poured straight from the can sits in lumps that never disperse in the oven.
Step 3: Slice the potatoes
Peel the potatoes if using russets, then slice them about 1/8 inch thick.
Slice them as close to assembly time as possible, since exposed potato discolours quickly.
Step 4: Layer
Arrange a third of the potato slices in the dish, slightly overlapping, and scatter a third of the sliced onion over them.
Season lightly, then pour over a third of the sauce.
Repeat twice more, finishing with sauce.
Step 5: Press it down
Press the top layer down firmly with a spatula so the sauce comes up around the slices.
Every slice needs contact with sauce. Any potato sitting above the liquid stays dry and leathery.
Step 6: Bake covered
Cover tightly with foil and bake for 50 minutes.
The foil traps steam, which is what cooks the potatoes through. Uncovered from the start, the top browns while the centre stays hard.
Step 7: Uncover and continue
Remove the foil and bake for another 25 to 35 minutes, until the top is golden and a knife slides through the centre with no resistance.
Step 8: Add the cheese, if using
Scatter the cheddar over the top in the final 10 minutes and return the dish uncovered until melted and bubbling.
Step 9: Rest before serving
Let the dish stand for 15 minutes before serving.
The sauce is loose straight from the oven and sets as it cools. Serving immediately gives you soup on the plate.
Tips for the Best Scalloped Potatoes
Slice thin and evenly. The single most important decision in the recipe.
Whisk the sauce separately. Lumps of condensed soup will not smooth themselves out during baking.
Cover for the first fifty minutes. Steam first, browning second.
Press the layers down. Potatoes above the sauce line dry out.
Test with a knife, not the clock. Ovens and potato varieties both vary. It should slide through with no resistance.
Common Mistakes to Avoid
Slicing too thick. The most common cause of undercooked potatoes in the middle of a browned casserole.
Baking uncovered the whole time. Burnt top, raw centre.
Rinsing the sliced potatoes. Washes away the starch that helps thicken the sauce.
Not enough liquid. The potatoes should be nearly submerged before baking. They absorb far more than expected.
Serving straight from the oven. Fifteen minutes is what turns a loose sauce into a set one.
Easy Variations
• Scalloped potatoes and ham. Layer in 2 cups of diced cooked ham. This is the classic use for leftover holiday ham.
• Cheesy. Add 1 cup of shredded cheddar between the layers as well as on top.
• Bacon and chive. Add 6 slices of cooked crumbled bacon between layers and finish with chives.
• From-scratch sauce. Make a roux with 4 tablespoons butter and 4 tablespoons flour, whisk in 3 cups of milk, and season.
• Slow cooker. Layer everything and cook on low for 5 to 6 hours.
• Half batch. Use an 8×8 dish and halve everything, baking for about 60 minutes total.
What to Serve With It
Ham is the traditional partner, and scalloped potatoes with ham is close to a fixed pairing on holiday tables.
Roast chicken, pork chops, meatloaf, or a beef roast all work.
Green beans, roasted carrots, or a sharp green salad balance the richness.
Something acidic helps. Pickles, a vinaigrette salad, or braised red cabbage cut through the cream.
Make-Ahead and Storage
Make-ahead: Assemble the whole dish, cover, and refrigerate for up to 24 hours. Add about 15 minutes to the covered baking time from cold. The potatoes may darken slightly, which disappears once baked.
Refrigerator: Store in an airtight container for up to 4 days.
Freezer: Freeze baked and cooled portions for up to 2 months. The texture softens slightly on thawing but holds up better than most cream-based potato dishes.
To reheat: Warm covered at 325°F for 20 to 25 minutes with a splash of milk added. The microwave works for single portions at 50 percent power.
Frequently Asked Questions
Why are my potatoes still hard?
Sliced too thick, or the dish was baked uncovered. Both prevent the centre cooking through.
What is the difference between scalloped and au gratin potatoes?
Scalloped potatoes are baked in a cream sauce. Au gratin includes cheese in the sauce and usually a breadcrumb topping.
Can I make it the night before?
Yes. Assemble, cover, and refrigerate for up to 24 hours, then add 15 minutes to the baking time.
Can I use a from-scratch sauce?
Yes. A roux of 4 tablespoons butter, 4 tablespoons flour, and 3 cups milk replaces both cans.
Why is my sauce watery?
It was served too soon, or the potatoes released liquid without enough time uncovered to reduce it. Rest for 15 minutes.
Do I need to peel the potatoes?
Peel russets. Yukon Golds and red potatoes have thin skins that can stay on.
Nutrition Information
Approximate values per serving, based on 10 servings:
• Calories: 275
• Total fat: 12 g
• Saturated fat: 6 g
• Carbohydrates: 34 g
• Fiber: 3 g
• Protein: 8 g
• Sodium: 720 mg
Nutrition is estimated and will vary with brands and portion sizes.
Final Thoughts
Easy scalloped potatoes are a ten-minute assembly with two rules attached: slice at an eighth of an inch, and keep the foil on for the first fifty minutes.
Whisk the sauce before it goes in, press the layers down so nothing sits above the liquid, and give the dish a full fifteen minutes to set before you serve it.