Au gratin potatoes have their place on Southern tables for almost every occasion. Rich, tender, and creamy potato casserole is elegant enough for a nice holiday dinner, but also humble enough for a weeknight meal, family dinner, or reunion potluck.

With less than 10 ingredients on the list, au gratin potatoes aren’t a difficult recipe either. In fact, the most complicated aspect of this potato gratin recipe is cutting the potatoes into thin slices. We recommend using a mandolin. This makes cutting uniform potato slices incredibly easy. Just be sure to use the guard or a cut-resistant glove to protect your fingertips.

Learn how to make au gratin potatoes and start planning your next menu for this classic side dish.

Ingredients for gratinated potatoes

This potato gratin recipe only requires eight ingredients:

• Yukon Gold Potatoes: These small, waxy yellow potatoes retain good texture and structure after cooking. White potatoes, like russets, can be a little too grainy.
• All-purpose flour: Thickens the cream sauce.
• Whole milk and butter: Makes the base sauce creamy and rich. You can also use half-and-half or cream, but skim milk wouldn’t work as well.
• Ground nutmeg, kosher salt and fresh thyme leaves: These provide delicate flavors and don’t overwhelm the potatoes and cream sauce. Nutmeg is used in many cream sauces. This adds a flavor that you usually can’t get with dairy and flour.
• Yellow onion: Adds a silky texture with a slight depth of savory flavor.

How to make au gratin potatoes

Au gratin potatoes are a very impressive dish. Good thing they’re also easy. Here’s a quick look at the recipe, and the full recipe is below.

Prepare the pan: To make this potato gratin recipe, first preheat the oven to 400°F and lightly coat a baking dish with cooking spray.

Prepare the sauce: Melt the butter in a saucepan, add the flour and cook, stirring constantly, until a dough forms and bubbles (but does not brown). Add the milk and bring to the boil. Reduce the heat and stir in the nutmeg and salt. Cook, whisking, until thickened before removing from the heat and setting aside.

Brown the onion: Heat the remaining butter in a non-stick pan and add the onion, thyme and salt. Cook until softened and remove from heat.

Build the casserole: Add a third of the potatoes to the prepared baking dish in a single layer. Top with half the onion mixture and a third of the cream sauce, and repeat layers until finished, finishing with the cream sauce on top.

Cover and cook the casserole: Bake, covered, for 30 minutes. Uncover and continue cooking until mixture is bubbling and golden brown, about 20 to 25 more minutes.

Let it rest: Remove the dish from the oven and let rest for 10 minutes before serving.

What does potato scallop mean?

Au gratin potatoes are thinly sliced, layered and cooked in a creamy sauce with flour, cream and butter. There are no actual scallops involved, despite what the name may suggest. In fact, the vegetable gratin technique simply means that the dish uses a cream sauce and sometimes breadcrumbs. To try Scalloped Corn Casserole Or Potatoes gratinated with ham following.

How to store au gratin potatoes

If you have leftovers, cover the casserole with foil and refrigerate for up to 4 days. If you only have one or two servings of potatoes, pour them into an airtight container. To reheat, you can use the microwave or reheat them in the oven.

Make-Ahead Instructions

Au gratin potatoes are an ideal side dish to prepare in advance. If you need to make these before a holiday meal or potluck, go ahead and assemble completely and cook the casserole according to the recipe. Then, let the dish cool to room temperature before wrapping it in foil and plastic wrap. Store in the refrigerator for up to two days.

Before serving, remove the dish from the refrigerator and allow it to come to room temperature before reheating it in a 350°F oven until heated through. This should take around 30 minutes.

Editorial contributions from Alexandre Dubin.