Old-Fashioned Scalloped Potatoes

Every holiday table at Grandma’s had a bubbling dish of scalloped potatoes on it, and every year somebody asked for the recipe like it was some great secret. It isn’t. It’s sliced potatoes, sweet onion, and a simple white sauce, baked slow until the top goes golden and the edges get those little crispy bits everybody fights over.

She sliced her potatoes by hand, thinner than you’d think possible, and she never once measured the sauce. This is her way, measured out properly so it comes out the same in your kitchen: tender layers all the way through, a sauce that stays creamy instead of curdling, and not a crunchy potato in the pan.

Make it for Thanksgiving, make it for Easter ham, make it on a plain Sunday when you want the house to smell like somebody loves you. It never lasts long, and the leftovers — if there are any — are even better the next day, crisped up in a skillet with a fried egg on top.

Don’t let the word “old-fashioned” fool you into thinking it’s fussy. There are no special ingredients and nothing to order ahead. If you can slice a potato and stir a sauce, you can make this dish — and once you’ve made it once, you’ll understand why it has outlasted every trend that ever came through Grandma’s kitchen.

Why This Recipe Works

• Paper-thin, even slices cook through at the same rate, so there are no hard, underdone potatoes hiding in the middle.
• A real stovetop white sauce poured over the layers stays silky in the oven — no separating, no curdling.
• Covered first, uncovered last: the foil traps steam to cook the potatoes tender, then comes off so the top can turn golden and bubbly.
• Resting before serving lets the sauce thicken and set, so you get neat scoops instead of potato soup.

Old-Fashioned Scalloped Potatoes

Thin-sliced potatoes and onions layered in a creamy homemade white sauce and baked until golden — the classic holiday side dish, just like Grandma made.

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Prep Time 20 minutes mins

Cook Time 1 hour hr 15 minutes mins

Total Time 1 hour hr 35 minutes mins

Servings: 8

Ingredients Method Notes

Ingredients

  

• 3 lb russet potatoes about 6 large, peeled and sliced 1/8 inch thick
• 1 medium yellow onion thinly sliced
• 3 tbsp butter plus more for the dish
• 3 tbsp all-purpose flour
• 2 cups whole milk
• 1/2 cup heavy cream or more milk
• 1 tsp salt
• 1/2 tsp black pepper
• 1/4 tsp garlic powder optional
• Pinch of nutmeg optional, but Grandma insisted
• Chopped fresh parsley for serving (optional)

Method

 

1. Preheat the oven to 350°F. Butter a 9×13-inch baking dish.
2. Melt the butter in a medium saucepan over medium heat. Whisk in the flour and cook 1 minute, stirring, until it smells faintly nutty.
3. Slowly pour in the milk and cream, whisking constantly to keep it smooth. Cook 3–4 minutes, stirring, until the sauce thickens enough to coat the back of a spoon. Season with the salt, pepper, garlic powder, and nutmeg. Remove from the heat.
4. Layer one-third of the potato slices in the dish, overlapping slightly. Scatter over one-third of the onion and pour over one-third of the sauce. Repeat the layers twice more, finishing with sauce.
5. Cover tightly with foil and bake 45 minutes.
6. Remove the foil and bake 25–30 minutes more, until the top is golden and bubbling and a knife slides into the center potatoes with no resistance.
7. Rest 10–15 minutes before serving so the sauce can set. Sprinkle with parsley if you like.

Notes

True scalloped potatoes have no cheese — add 1 cup of shredded sharp cheddar between the layers  and you’ve made potatoes au gratin, which Grandma allowed at Easter.  Slice the potatoes just before assembling so they don’t turn gray.

Grandma’s Tips

1. Even slices matter more than thin ones. If you have a mandoline, use it — carefully, with the guard. A steady knife and patience work too.
2. Warm your milk before adding it to the roux and the sauce comes together faster with no lumps.
3. Don’t rinse the sliced potatoes. The surface starch helps thicken the sauce as it bakes.
4. Make it ahead: assemble the whole dish, cover, and refrigerate up to a day ahead. Add 10–15 minutes to the covered baking time.
5. Test the middle, not the edge. The center slices cook slowest — that’s where your knife should check for tenderness.
6. A cast-iron or ceramic dish holds the heat evenly and gives you the prettiest golden edges for the table.

Frequently Asked Questions

What’s the difference between scalloped potatoes and au gratin?

Scalloped potatoes are baked in a cream or milk sauce with no cheese. Au gratin adds cheese and often a breadcrumb top. Both are wonderful; this is the classic scalloped version.

Why did my sauce curdle?

Usually the oven was too hot or the sauce was too thin to start. Baking at 350°F and making a proper roux-based sauce keeps it smooth and creamy.

Can I use a different potato?

Russets give the creamiest result because their starch thickens the sauce. Yukon Golds work nicely too and hold their shape a bit more. Red potatoes stay firmer and are Grandma’s last choice for this dish.

How do I store and reheat leftovers?

Cover and refrigerate up to 4 days. Reheat, covered with foil, at 325°F for about 20 minutes, with a spoonful of milk drizzled over the top to bring back the creaminess.