Introduction

This Cheesy Root Vegetable Gratin is a comforting and flavorful dish perfect for any season. Layered with tender Yukon Gold potatoes, sweet potatoes, and parsnips, it’s richly infused with garlic, herbs, and a creamy cheese blend that bakes to golden perfection.

A white oval dish holds neatly arranged layers of sliced vegetables in rows, each slice thin and standing upright. Starting from the left, the first row is bright orange sweet potatoes, showing a soft and slightly crisp texture. Next to it is a row of creamy white potatoes, baked with a golden, bubbly cheese topping. In the middle, rich red tomatoes are sliced thin and stacked closely, looking juicy and tender. To the right of the tomatoes, there is another row of white potatoes with a similar cheese crust. Finally, the far right row has dark purple eggplant slices, roasted to a slightly charred finish. The whole dish is sprinkled with small green herbs, adding freshness. A silver spoon rests at the edge inside the dish, all set on a white marbled surface. Photo taken with an iphone --ar 4:5 --v 7

Ingredients

1 tablespoon olive oil
1 large onion, thinly sliced
2 cloves garlic, minced
1 teaspoon dried thyme
1/2 teaspoon dried rosemary
1/4 teaspoon ground nutmeg
1 pound Yukon Gold potatoes, peeled and thinly sliced (about 1/8 inch thick)
1 pound sweet potatoes, peeled and thinly sliced (about 1/8 inch thick)
1 pound parsnips, peeled and thinly sliced (about 1/8 inch thick)
1 cup heavy cream
1 cup whole milk
1/2 teaspoon salt, or to taste
1/4 teaspoon black pepper, or to taste
8 ounces Gruyere cheese, shredded (about 2 cups)
4 ounces Parmesan cheese, finely grated (about 1 cup)
2 tablespoons butter, cut into small pieces
Fresh parsley, chopped, for garnish (optional)

Instructions

Step 1: In a large skillet, heat the olive oil over medium heat. Add the sliced onion and cook, stirring occasionally, until softened and translucent, about 8-10 minutes.
Step 2: Add the minced garlic, dried thyme, and dried rosemary to the skillet. Cook for another minute, stirring constantly, until fragrant.
Step 3: Stir in the ground nutmeg, then remove the skillet from heat and set aside.
Step 4: Preheat your oven to 375°F (190°C) and grease a 9×13 inch baking dish with butter or cooking spray.
Step 5: Arrange about one-third of the potato slices in a single layer on the bottom of the baking dish, slightly overlapping.
Step 6: Layer one-third of the sweet potato slices over the potatoes, slightly overlapping.
Step 7: Add one-third of the parsnip slices over the sweet potatoes, slightly overlapping.
Step 8: Spoon one-third of the sautéed onion and garlic mixture evenly over the vegetables.
Step 9: Sprinkle one-third of the Gruyere and Parmesan cheeses over the onion mixture.
Step 10: Repeat the layering process two more times with the remaining vegetables, onion mixture, and cheeses, ending with cheese on top.
Step 11: In a medium bowl, whisk together the heavy cream and whole milk. Stir in salt and pepper, adjusting seasoning to taste.
Step 12: Carefully pour the cream mixture over the layered vegetables and cheese, ensuring the liquid seeps through. Gently press down if needed; the cream should almost cover the top layer.
Step 13: Dot the top with the butter pieces, then cover the dish tightly with aluminum foil.
Step 14: Bake in the preheated oven for 45 minutes.
Step 15: Remove the foil and continue baking for another 30-45 minutes, until the vegetables are tender and the top is golden and bubbly. If browning too fast, tent loosely with foil.
Step 16: Let the gratin rest for 15-20 minutes before serving.

Tips & Variations

Use a mandoline slicer to ensure uniform thin slices for even cooking.
Swap Gruyere with Fontina or cheddar for a different cheese flavor.
Add a pinch of smoked paprika or cayenne for a subtle smoky heat.
For a richer dish, use all heavy cream instead of mixing with milk.
Garnish with fresh parsley right before serving for a fresh touch.

Storage

Store leftovers in an airtight container in the refrigerator for up to 3 days. Reheat gently in a 350°F (175°C) oven covered with foil until warmed through to maintain creaminess and avoid drying out.

How to Serve

In a white oval baking dish filled with creamy melted cheese at the bottom, there are two rows of thinly sliced vegetables arranged standing up. One row has several layers of orange and deep red slices, slightly crispy and dusted with green herbs. The other row next to it has many layers of golden yellow to light orange slices, also topped with green herbs. A silver spoon rests inside the dish, leaning against the side of the vegetable rows. The dish sits on a white marbled surface. photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I prepare the gratin ahead of time?

Yes, you can assemble the gratin a few hours ahead and keep it covered in the refrigerator. Bake it just before serving, adding a few extra minutes to the baking time if needed.

Can I use other root vegetables in this gratin?

Absolutely! Carrots, turnips, or rutabagas work well and will add interesting flavors and textures to the dish.