1. Preheat Oven and Prepare Potatoes:
- Preheat your oven to 375°F (190°C). Lightly grease a 9×13 inch baking dish.
- Peel and thinly slice the potatoes. A mandoline works best for getting consistently thin slices. Set aside.
2. Make the Cheese Sauce:
- In a saucepan over medium heat, melt the butter. If using, sauté the onion and garlic until translucent and fragrant.
- Stir in the flour to form a roux. Cook for about 2 minutes, stirring constantly, to cook off the raw flour taste.
- Gradually whisk in the milk and heavy cream, ensuring there are no lumps. Bring to a simmer, and cook until the sauce thickens, about 5 minutes.
- Remove from heat and stir in the salt, pepper, nutmeg (if using), cheddar cheese, and half of the Parmesan cheese until smooth.
3. Assemble the Dish:
- Arrange a layer of sliced potatoes at the bottom of the prepared baking dish. Pour a portion of the cheese sauce over the potatoes. Repeat the layers until all the potatoes and sauce are used, finishing with a layer of sauce.
- Sprinkle the remaining Parmesan cheese and some additional cheddar cheese on top.
4. Bake:
- Cover the dish with foil and bake for 1 hour. Then, remove the foil and bake for an additional 15-20 minutes, or until the top is golden and bubbly, and the potatoes are tender.
5. Serve:
- Let the dish stand for about 10 minutes before serving. This allows the sauce to thicken slightly and makes serving easier.
Tips:
- Slicing Potatoes: Ensure the potatoes are sliced evenly so they cook at the same rate.
- Layering: Ensure each layer of potatoes is covered generously with the cheese sauce for the creamiest texture.
- Variations: Feel free to add layers of cooked bacon, ham, or sautéed mushrooms between the potatoes for added flavor.
Potatoes Delmonico is a rich and comforting side dish that adds a touch of elegance to any meal. Enjoy the creamy, cheesy goodness alongside your favorite main dishes.