Description
Creamy, cheesy Potatoes au Gratin deliver pure comfort with layers of golden potato slices melted beneath a rich, bubbling cheese sauce. Crisp edges and smooth interior make this classic French side dish a crowd-pleasing favorite you’ll crave at every gathering.
Ingredients
Scale
Potatoes
- 2.5 pounds (1.1 kilograms) red potatoes
- 1 onion
Cheese and Dairy
- 1 cup cheddar cheese, shredded
- 1/2 cup gruyere cheese, shredded
- 2 cups (480 milliliters) milk
- 3 tablespoons (45 grams) butter
Seasonings and Thickeners
- 3 tablespoons all-purpose flour
- 1 teaspoon dry mustard powder
- Salt to taste
- Pepper to taste
Instructions
- Heat oven to 375F (190C) and generously grease a ceramic baking dish to prevent sticking.
- Using a sharp mandoline or knife, create translucent, uniform slices of potatoes and onions approximately 1/8 inch thick.
- In a medium saucepan, melt butter over moderate heat, then whisk in flour and mustard powder until a smooth, pale roux forms without browning.
- Slowly stream milk into the roux, continuously whisking to eliminate potential lumps and create a silky, thickening sauce.
- Remove sauce from heat and incorporate cheddar and gruyere cheeses, stirring until completely melted and achieving a glossy, uniform consistency.
- Season the cheese sauce with salt and freshly ground black pepper, tasting to ensure balanced flavor.
- Arrange a single layer of potato and onion slices across the bottom of the prepared baking dish, slightly overlapping for even coverage.
- Drizzle half the cheese sauce evenly over the first layer, ensuring all potato and onion surfaces are coated.
- Create a second identical layer with remaining potatoes, onions, and finish with the remaining cheese sauce.
- Cover the dish tightly with aluminum foil and bake for 45 minutes to allow potatoes to become tender.
- Remove foil and continue baking for 15-20 minutes until the top develops a golden, crispy crust and edges are bubbling.
Notes
- Choose starchy potatoes like Russet or Yukon Gold for the creamiest, most melt-in-your-mouth texture that absorbs cheese sauce perfectly.
- Slice potatoes uniformly using a mandoline slicer to ensure even cooking and consistent layers throughout the dish.
- Rinse potato slices in cold water to remove excess starch, which helps prevent them from sticking together and creates a lighter, fluffier gratin.
- For a lighter version, substitute half-and-half or whole milk with low-fat milk and use reduced-fat cheeses without compromising rich, comforting flavor.
- Prep Time: 30 minutes
- Cook Time: 1 hour 15 minutes
- Category: Dinner, Appetizer, Snacks
- Method: Baking
- Cuisine: French
Nutrition
- Serving Size: 6
- Calories: 250 kcal
- Sugar: 3 g
- Sodium: 320 mg
- Fat: 15 g
- Saturated Fat: 9 g
- Unsaturated Fat: 5 g
- Trans Fat: 0.2 g
- Carbohydrates: 20 g
- Fiber: 2 g
- Protein: 10 g
- Cholesterol: 40 mg