Description
Potato lovers rejoice with this classic French side dish of creamy cheesy potatoes au gratin. Layers of thinly sliced potatoes meld with rich cheese and cream, creating a luxurious comfort dish you’ll savor down to the last delectable bite.
Ingredients
Scale
Vegetables:
- 2.5 pounds (1.13 kilograms) red potatoes, thinly sliced
- 1 large onion, thinly sliced
Dairy and Cheese:
- 2 cups (473 milliliters) milk
- 3 tablespoons (45 milliliters) butter
- 1 cup (226 grams) cheddar cheese, shredded
- 0.5 cup (113 grams) gruyere cheese, shredded
Seasonings and Thickeners:
- 3 tablespoons (45 milliliters) flour
- 1 teaspoon (5 milliliters) dry mustard powder
- Salt, to taste
- Pepper, to taste
Instructions
- Preheat the oven to 400°F (200°C) and thoroughly coat a 2.5 to 3-quart casserole dish with cooking spray or butter to prevent sticking.
- Meticulously scrub potatoes under cool running water, then use a sharp mandoline or knife to create uniform ⅛-inch translucent slices.
- Carefully dice the onion into delicate, gossamer-thin rings, ensuring consistent width for even cooking.
- Arrange potato slices vertically in an overlapping, accordion-like pattern within the prepared casserole dish, interspersing onion slices between potato layers.
- In a heavy-bottomed saucepan, melt butter over medium heat until it becomes slightly foamy and golden.
- Incorporate flour into the melted butter, whisking continuously to create a smooth, light roux that develops a nutty aroma without burning.
- Gradually introduce dry mustard, milk, salt, and pepper, stirring constantly to prevent lumps and create a velvety, consistent sauce.
- Remove sauce from heat and fold in shredded cheeses, stirring until they melt completely and blend into a luxurious, glossy mixture.
- Gently cascade the cheese sauce over the potato and onion arrangement, ensuring each slice is thoroughly coated.
- Cover the dish with lightly greased aluminum foil and bake for 60 minutes, allowing potatoes to steam and become tender.
- Uncover the dish and return to the oven, baking an additional 25-30 minutes until the surface turns a rich, golden-brown and potatoes are completely soft when pierced with a fork.
- Let the gratin rest for 15-20 minutes, allowing the layers to settle and sauce to slightly thicken before serving.
Notes
- Carefully stacking potatoes vertically maximizes surface area, ensuring each slice gets perfectly crispy and coated with luxurious cheese sauce.
- Letting the dish rest after baking allows flavors to meld and creates a more stable texture, preventing a runny or messy serving experience.
- Prep Time: 20 minutes
- Cook Time: 90 minutes
- Category: Dinner, Side Dish
- Method: Baking
- Cuisine: French
Nutrition
- Serving Size: 6
- Calories: 360
- Sugar: 3 g
- Sodium: 500 mg
- Fat: 18 g
- Saturated Fat: 11 g
- Unsaturated Fat: 5 g
- Trans Fat: 0 g
- Carbohydrates: 40 g
- Fiber: 3 g
- Protein: 10 g
- Cholesterol: 45 mg