Air Fryer Scalloped Potatoes (Cheesy Potato Gratin).

Prep Time: 15 minutes
Cook Time: 35 to 40 minutes
Resting Time (The Final Step): 10 minutes
Total Time: 1 hour
Yield: 4 to 6 servings
Skill Level / Intensity: Easy to Intermediate. (The primary intensity point is slicing the potatoes uniformly thin and managing the cream reduction to prevent scorching).
Course: Side Dish / Casserole
Cuisine: Modern American / French-Inspired Comfort Food

To build layers of rich flavor and ultimate creaminess, make sure to gather and measure your ingredients ahead of time:

For the Potato Gratin Base:

Potatoes: 2 pounds (about 3 medium-large) Yukon Gold or Russet potatoes, peeled and sliced uniformly thin (approx. 1/8-inch thick using a mandoline or sharp knife).
Butter: 2 tablespoons unsalted butter, melted (plus extra for greasing the baking dish).
Garlic: 2 cloves fresh garlic, minced or pressed.
Cheese: 1.5 cups freshly shredded Gruyère, sharp white cheddar, or a gourmet melting blend.
Seasonings:
- 3/4 teaspoon kosher salt
- 1/2 teaspoon freshly ground black pepper
- 1/4 teaspoon ground nutmeg (classic for potato gratins, adding a subtle warmth)
- A pinch of smoked paprika (optional, for the top garnish)

For the Cream Sauce:

Heavy Cream: 1 cup heavy whipping cream (do not substitute with milk, as heavy cream prevents curdling under high heat).
Chicken or Vegetable Broth: 1/4 cup low-sodium broth to balance the richness.
Parmesan Cheese: 1/3 cup freshly grated Parmesan cheese (for an extra savory depth in the sauce).

Preheat your air fryer to 350°F (175°C) for about 3 to 5 minutes so it is hot and ready to accept your baking dish.
Select a small, oven-safe baking dish or cake pan that safely fits inside your specific air fryer basket (typically a 6-inch or 7-inch round or square dish works best). Generously grease the interior of the dish with melted butter or non-stick spray.

Peel your potatoes and slice them uniformly to about 1/8-inch thickness. Uniformity is key to ensuring they cook evenly at the exact same rate. Pro-tip: If using a mandoline slicer, use extreme caution and a safety glove.
Rinse the potato slices briefly in cold water to remove excess surface starch, then pat them completely dry with clean paper towels.

In a medium mixing bowl, whisk together the 1 cup of heavy whipping cream, 1/4 cup of broth, minced garlic, melted butter, kosher salt, black pepper, and ground nutmeg.
Stir in the 1/3 cup of freshly grated Parmesan cheese until well incorporated.

Arrange a tight, slightly overlapping single layer of potato slices across the bottom of your prepared baking dish.
Sprinkle a small handful of your shredded Gruyère or cheddar cheese over the potatoes, along with a few spoonfuls of the seasoned cream mixture.
Repeat the layers—potatoes, cheese, and cream sauce—until all the potatoes are used up, pressing down gently every few layers to compact the stack. Pour any remaining cream mixture evenly over the very top layer.
Top the final layer with the remaining shredded cheese and a tiny pinch of smoked paprika for a stunning visual color finish.

Carefully place the loaded baking dish into your preheated air fryer basket.
Cover the top of the baking dish loosely with a small piece of aluminum foil to prevent the cheese from burning before the potatoes inside have a chance to cook through.
Cook at 350°F (175°C) for 25 minutes.
Carefully remove the foil lid, and continue air frying for an additional 10 to 15 minutes. Watch closely during this window; you want the top cheese layer to turn a deep, bubbling golden-brown and the edges to crisp up delightfully. Test the doneness by inserting a sharp paring knife into the center—it should slide through the potato layers with zero resistance.

The Resting Phase: Remove the baking dish from the air fryer using heat-resistant oven mitts. Place it on a wire cooling rack and let it rest undisturbed for 10 to 15 minutes.
Why is this final step mandatory? Freshly baked potato gratin is molten hot, and the heavy cream and melted cheese need time to cool and re-emulsify. If you try to scoop it immediately, the portions will collapse into a runny soup. Resting allows the starch and cream to tighten up into a gorgeous, cohesive sauce that holds its shape cleanly on the plate.
Spoon generous portions onto serving plates, letting the decadent, garlic-infused cream sauce coat every single potato slice. Serve immediately alongside your favorite main protein.

Foil Security: Ensure your foil covering is tucked securely around the edges of your baking dish inside the air fryer. The powerful convection fan blowing air inside the basket can easily lift loose foil and blow it directly onto the heating element, causing smoke or a ruined dish.
Cheese Selection: While Gruyère provides the ultimate traditional nutty gratin flavor, a combination of sharp white cheddar and fontina melts like an absolute dream and creates a gorgeous golden crust.
Potato Choice: Stick strictly to high-starch or all-purpose varieties like Yukon Golds. Waxy red potatoes will remain unpleasantly firm and will not absorb the rich cream properly during the air fryer cycle.

Note: Nutritional estimates are based on 1/6th of the total recipe yield.