Detailed Step-by-Step Instructions for Perfect Scalloped Potatoes

Step 1: Preheat the Oven

1. Turn on your oven and set it to 375°F (190°C). This ensures the oven is fully heated by the time you’re ready to bake.

2. While the oven heats, prepare your baking dish. Take a 9x13-inch baking dish and grease it thoroughly with butter or cooking spray. This prevents the potatoes from sticking and makes cleanup easier.

Step 2: Prepare the Creamy Sauce

1. In a medium saucepan, melt 4 tablespoons (½ stick) of unsalted butter over medium heat. Keep an eye on it to avoid burning.

2. Once the butter is melted, whisk in ¼ cup of all-purpose flour. Stir constantly for 1-2 minutes until the mixture turns golden and bubbly. This step cooks the raw flour taste out and creates a roux, which will thicken the sauce.

3. Slowly pour in 2 cups of whole milk and 1 cup of chicken or vegetable broth, whisking constantly to prevent lumps from forming. A steady pour and consistent whisking are key to a smooth sauce.

4. Add 1 teaspoon of dried thyme, 1 teaspoon of salt, and ½ teaspoon of black pepper. Stir to combine.

5. Continue cooking the sauce over medium heat, stirring frequently, until it thickens enough to coat the back of a spoon. This should take about 5 minutes. Once thickened, remove the saucepan from the heat and set it aside.

Step 3: Slice the Potatoes and Onions

1. While the sauce is thickening, prepare your potatoes and onions:

   • Peel 4 large russet potatoes (or Yukon Gold for a creamier texture).

   • Slice the potatoes into ⅛-inch thick rounds using a sharp knife, mandoline slicer, or food processor. Consistent thickness ensures even cooking.

   • Thinly slice 1 medium onion into half-moons. This adds a subtle sweetness to the dish.

Step 4: Layer the Potatoes and Cheese

1. Begin assembling the dish:

   • Arrange a single layer of potato slices in the bottom of the greased baking dish, slightly overlapping them like shingles.

   • Scatter a handful of the sliced onions evenly over the potatoes.

   • Sprinkle ½ cup of shredded Gouda cheese and ¼ cup of grated Parmesan cheese over the onions. The combination of cheeses adds depth of flavor.

2. Repeat the layering process until all the potatoes, onions, and cheese are used. Aim for 3-4 layers, finishing with a final layer of cheese on top.

Step 5: Add the Creamy Sauce

1. Pour the prepared creamy sauce evenly over the layered potatoes. Use a spatula to gently spread the sauce, ensuring it seeps into all the layers.

2. If desired, sprinkle an extra ¼ cup of Parmesan cheese on top for a golden, cheesy crust.

Step 6: Bake the Scalloped Potatoes

1. Cover the baking dish tightly with aluminum foil. This traps steam and helps the potatoes cook through without drying out.

2. Place the dish in the preheated oven and bake for 45 minutes.

3. After 45 minutes, remove the foil and bake for an additional 15-20 minutes, or until the top is golden brown, bubbly, and the potatoes are tender when pierced with a fork.

Step 7: Rest and Serve

1. Once baked, remove the dish from the oven and let it rest for 10-15 minutes. This allows the sauce to set slightly, making it easier to serve.

2. Garnish with freshly chopped parsley or chives for a pop of color and freshness.

3. Serve warm as a side dish with roasted meats, grilled chicken, or your favorite holiday meal.

Tips for Success:

• Potato Slicing: Use a mandoline slicer for even, thin slices. If using a knife, take your time to ensure uniformity.

• Cheese Variations: Feel free to experiment with other cheeses like cheddar, Gruyère, or fontina for different flavor profiles.

• Make-Ahead Option: Assemble the dish up to a day in advance, cover, and refrigerate. Add an extra 10-15 minutes to the baking time if starting from cold.

• Creamier Texture: For an even richer dish, substitute half-and-half or heavy cream for the milk.