Cheesy Scalloped Potatoes (Potatoes Au Gratin)

Ingredients

• 2 lb moderate-starch potatoes (Thinly sliced; Russets absorb more liquid, while Yukon Golds are creamier.)
• 3 tbsp butter
• 3 tbsp all-purpose flour
• 0.5 cup yellow onion (Finely chopped.)
• 0.5 cup leeks (Finely chopped.)
• 2 cloves garlic (Minced.)
• 2 cups whole milk
• 0.5 cup heavy cream
• 1.5 tsp salt
• 0.25 tsp freshly ground black or white pepper (Optional.)
• 1.5 cups Cheddar cheese (Shredded; do not use pre-shredded, as it does not melt as well.)
• 0.333333 cup Parmesan cheese (Grated and divided in half.)
• 1 cup Gruyère cheese (Grated.)
• 1 tsp nutmeg
• 1 tsp paprika
• 1 tsp Dijon mustard (Optional.)
• parsley (Chopped, for garnish.)

Steps

1. 1

   Preheat the oven to 350°F.

2. 2

   Heat the butter in a large saucepan over medium-high heat.

3. 3

   Add the chopped onion and leeks. Cook for 5–6 minutes, until soft and translucent.

4. 4

   Add the minced garlic and cook for another minute.

5. 5

   Add the flour, nutmeg, paprika, and pepper. Stir to combine and cook for 1–2 minutes.

6. 6

   Add the milk, Dijon mustard, and heavy cream, stirring continually to prevent clumping.

7. 7

   Slowly bring the mixture to a boil, then reduce the heat and simmer until slightly thickened.

8. 8

   Add the Cheddar, half of the grated Parmesan, and Gruyère. Stir until the cheeses have melted.

9. 9

   Arrange the sliced potatoes in a casserole dish, layering them into rows if desired.

10. 10

    Pour the cheese sauce over the potatoes.

11. 11

    Sprinkle the remaining Parmesan over the top, then cover the dish with foil.

12. 12

    Bake for 45 minutes to 1 hour, or until the potatoes are tender. The time may vary depending on how thickly the potatoes are sliced.

13. 13

    Uncover and bake for another 20 minutes, or until the top is lightly browned.

14. 14

    Let the potatoes sit for about 5 minutes before serving.

15. 15

    Garnish with chopped parsley and serve.

Notes

The recipe describes this as a suitable make-ahead side dish but does not provide specific make-ahead, storage, or reheating instructions.

Nutrition per serving

• side dish
• vegetarian
• holiday
• make-ahead
• baked
• potatoes
• cheesy
• gluten-containing