Mom’s Scalloped Potato Gratin: A Comfort Food Classic

There’s something undeniably comforting about a warm, bubbling dish of scalloped potatoes. It’s a dish that evokes memories of family gatherings, cozy dinners, and the simple pleasure of good food. This recipe, inspired by my mom’s own, takes the classic scalloped potatoes to the next level with a rich, creamy gratin topping. It’s a guaranteed crowd-pleaser, perfect for holidays, potlucks, or a special weeknight meal.

## Why This Recipe Works

This isn’t just another scalloped potato recipe. Here’s what makes it special:

* **Creamy, Not Gluey:** We avoid the dreaded gluey texture by using a combination of heavy cream and milk, along with a roux-based sauce. This creates a luscious, smooth sauce that coats the potatoes beautifully.
* **Flavor Depth:** The addition of nutmeg, garlic, and thyme adds layers of flavor that elevate the dish beyond the ordinary. The caramelized onions provide a sweet and savory note that complements the potatoes perfectly.
* **Gratin Topping:** The Gruyère and Parmesan cheese gratin topping creates a golden-brown, bubbly crust that adds a delightful textural contrast to the creamy potatoes underneath.
* **Even Cooking:** Slicing the potatoes thinly and arranging them in even layers ensures that they cook evenly throughout the dish.
* **Make-Ahead Friendly:** You can assemble the gratin ahead of time and bake it later, making it perfect for entertaining.

## Ingredients

Here’s what you’ll need to make Mom’s Scalloped Potato Gratin:

* **Potatoes:** 3 pounds Yukon Gold potatoes, peeled and thinly sliced (about 1/8 inch thick).
* **Onion:** 1 large yellow onion, thinly sliced.
* **Garlic:** 2 cloves garlic, minced.
* **Butter:** 4 tablespoons unsalted butter, divided.
* **All-Purpose Flour:** 4 tablespoons all-purpose flour.
* **Milk:** 2 cups whole milk.
* **Heavy Cream:** 1 cup heavy cream.
* **Nutmeg:** 1/4 teaspoon ground nutmeg.
* **Thyme:** 1 teaspoon dried thyme.
* **Salt and Black Pepper:** To taste.
* **Gruyère Cheese:** 1 cup grated Gruyère cheese.
* **Parmesan Cheese:** 1/2 cup grated Parmesan cheese.
* **Optional:** 2 tablespoons chopped fresh parsley, for garnish.

## Equipment

* 9×13 inch baking dish
* Large saucepan
* Mandoline or sharp knife
* Whisk
* Grater

## Step-by-Step Instructions

Follow these detailed instructions for perfect scalloped potato gratin every time:

**1. Prepare the Potatoes and Onions:**

* Peel the potatoes and slice them thinly using a mandoline or a sharp knife. Aim for slices about 1/8 inch thick. Consistent thickness is key for even cooking.
* Place the sliced potatoes in a bowl of cold water to prevent them from browning and to remove excess starch.
* Thinly slice the onion.
* Mince the garlic.

**2. Sauté the Onions and Garlic:**

* In a large saucepan, melt 2 tablespoons of butter over medium heat.
* Add the sliced onion and cook, stirring occasionally, until softened and lightly caramelized, about 10-15 minutes. This step adds a depth of flavor to the gratin.
* Add the minced garlic and cook for another minute until fragrant. Be careful not to burn the garlic.
* Remove the onion and garlic from the saucepan and set aside.

**3. Make the Cream Sauce:**

* In the same saucepan, melt the remaining 2 tablespoons of butter over medium heat.
* Whisk in the flour and cook for 1-2 minutes, stirring constantly, to create a roux. This will help thicken the sauce.
* Gradually whisk in the milk, making sure to break up any lumps. Continue whisking until the sauce is smooth.
* Whisk in the heavy cream.
* Bring the sauce to a simmer, stirring constantly, and cook until it thickens slightly, about 5-7 minutes. The sauce should be thick enough to coat the back of a spoon.
* Remove the saucepan from the heat.
* Stir in the nutmeg, thyme, salt, and pepper to taste. Don’t be shy with the seasoning! Remember that the potatoes will absorb some of the salt.

**4. Assemble the Gratin:**

* Preheat oven to 375°F (190°C).
* Grease the 9×13 inch baking dish with butter or cooking spray.
* Drain the sliced potatoes and pat them dry with paper towels. This is important to prevent a watery gratin.
* Arrange a layer of potato slices in the bottom of the baking dish, overlapping them slightly.
* Sprinkle some of the caramelized onions and garlic over the potatoes.
* Pour about one-third of the cream sauce over the potatoes and onions, making sure to coat them evenly.
* Repeat the layers: potatoes, onions and garlic, cream sauce, until all the potatoes and onions are used. Make sure the top layer is potatoes and that it’s evenly covered with cream sauce.

**5. Add the Gratin Topping:**

* In a bowl, combine the grated Gruyère cheese and Parmesan cheese.
* Sprinkle the cheese mixture evenly over the top of the potatoes and cream sauce.

**6. Bake the Gratin:**

* Cover the baking dish with aluminum foil. This will help the potatoes cook through without the top browning too quickly.
* Bake for 45 minutes.
* Remove the foil and bake for another 15-20 minutes, or until the cheese is melted, golden brown, and bubbly. The potatoes should be tender when pierced with a fork.
* If the top is browning too quickly, you can loosely cover it with foil again.

**7. Rest and Serve:**

* Remove the gratin from the oven and let it rest for at least 10-15 minutes before serving. This allows the sauce to thicken slightly and the flavors to meld together.
* Garnish with chopped fresh parsley, if desired.
* Serve hot and enjoy!

## Tips for Success

* **Use the Right Potatoes:** Yukon Gold potatoes are ideal for scalloped potatoes because they have a creamy texture and hold their shape well during cooking. Russet potatoes can also be used, but they tend to be starchier and may require more liquid.
* **Slice the Potatoes Thinly:** Consistent, thin slices are crucial for even cooking. A mandoline makes this task much easier, but a sharp knife will also work.
* **Don’t Overcook the Sauce:** Cook the cream sauce until it’s thick enough to coat the back of a spoon, but don’t overcook it, or it will become too thick.
* **Season Generously:** Potatoes tend to absorb salt, so don’t be afraid to season the sauce and the potatoes generously.
* **Use High-Quality Cheese:** Gruyère and Parmesan cheese provide a rich, nutty flavor that complements the potatoes perfectly. Don’t skimp on the cheese!
* **Let it Rest:** Resting the gratin after baking allows the sauce to thicken and the flavors to meld together. This is an important step that shouldn’t be skipped.

## Variations

Here are a few ideas for customizing Mom’s Scalloped Potato Gratin:

* **Add Bacon or Ham:** Cooked and crumbled bacon or diced ham can be added between the layers of potatoes for a smoky, savory flavor.
* **Include Vegetables:** Sautéed mushrooms, spinach, or leeks can be added to the gratin for extra nutrients and flavor.
* **Spice it Up:** Add a pinch of red pepper flakes to the cream sauce for a little heat.
* **Use Different Cheeses:** Experiment with different cheeses in the gratin topping, such as cheddar, fontina, or mozzarella.
* **Make it Vegetarian:** Use vegetable broth instead of milk for a vegetarian version.

## Make-Ahead Instructions

This scalloped potato gratin can be assembled ahead of time and baked later. Here’s how:

1. Assemble the gratin according to the instructions up to the point of baking.
2. Cover the baking dish tightly with plastic wrap and refrigerate for up to 24 hours.
3. When ready to bake, remove the plastic wrap and bake as directed, adding an extra 10-15 minutes to the baking time if necessary.

## Serving Suggestions

Mom’s Scalloped Potato Gratin is a versatile side dish that pairs well with a variety of main courses, including:

* Roasted chicken or turkey
* Beef tenderloin or steak
* Pork chops
* Ham
* Salmon or other fish
* Vegetarian roasts

It’s also delicious on its own as a comforting vegetarian meal.

## Storage Instructions

* **Refrigerate:** Leftover scalloped potato gratin can be stored in an airtight container in the refrigerator for up to 3-4 days.
* **Reheat:** To reheat, bake in a preheated oven at 350°F (175°C) until heated through, or microwave in short intervals until warm. Be careful not to overheat, as this can dry out the potatoes.

## Nutritional Information (Approximate)

* Calories: 450-550 per serving (depending on ingredients and serving size)
* Fat: 30-40g
* Saturated Fat: 18-25g
* Cholesterol: 100-150mg
* Sodium: 300-400mg
* Carbohydrates: 30-40g
* Fiber: 3-5g
* Protein: 15-20g

## Conclusion

Mom’s Scalloped Potato Gratin is a classic comfort food dish that’s perfect for any occasion. With its creamy texture, rich flavor, and golden-brown gratin topping, it’s sure to become a family favorite. So gather your ingredients, follow these instructions, and get ready to enjoy a truly delicious and satisfying meal. This recipe is a tribute to the simple, heartwarming dishes that mothers everywhere have been making for generations. Enjoy!