🔹 Step 1: Prep and Preheat
Preheat oven to 375°F (190°C).

Grease a 9×13-inch baking dish with butter or cooking spray.

🔹 Step 2: Slice the Potatoes
Peel and slice potatoes into ⅛-inch thick rounds using a mandoline or sharp knife.

📌 Uniform slices ensure even cooking. Place slices in a bowl of cold water to prevent browning (optional).

🔹 Step 3: Make the Cream Sauce
In a medium saucepan, melt butter over medium heat.

Add onion and sauté until soft (about 3–4 minutes).

Stir in garlic and cook for 30 seconds.

Sprinkle in flour, whisking constantly to form a roux (1–2 minutes).

Slowly whisk in milk, then cream, and cook until slightly thickened (about 3–5 minutes).

Add salt, pepper, and nutmeg.

Remove from heat and stir in 1 cup cheddar cheese until melted and smooth.

🔹 Step 4: Layer the Potatoes
Drain and pat the potatoes dry.

Arrange half of the sliced potatoes in the bottom of the baking dish.

Pour half the cream sauce over the potatoes.

Repeat with remaining potatoes and the rest of the sauce.

Sprinkle the top with the remaining ½ cup cheddar and mozzarella or Gruyère (if using).

🔹 Step 5: Bake
Cover the dish with foil and bake for 45 minutes.

Uncover and bake an additional 20–30 minutes, or until the top is golden and bubbly and the potatoes are fork-tender.

💡 Let rest for 10–15 minutes before serving to allow the sauce to thicken.

🍽️ Garnish & Serve
Sprinkle with chopped fresh parsley or thyme for a fresh finish.

Serve warm alongside ham, chicken, steak, or roasted veggies.

🔁 Variations
Cheesy Scalloped Potatoes: Add more cheese like Parmesan or smoked Gouda.

Loaded Version: Add chopped cooked bacon or caramelized onions between layers.

Herbed: Mix in rosemary or thyme to the sauce for extra flavor.

🧺 Storage & Reheating
Fridge: Store leftovers in an airtight container up to 4 days.

Reheat: In the oven at 350°F (covered with foil) or microwave in portions.

Freeze: Wrap tightly and freeze up to 2 months. Thaw overnight in the fridge and reheat in oven.