Cheesy Root Vegetable Gratin is a hearty and cozy dish that’s full of tender, earthy root veggies covered in a bubbly, golden layer of melted cheese. Think of tender slices of carrots, parsnips, and potatoes all baked together until soft and flavorful, with a creamy cheese sauce that makes every bite feel warm and comforting.
I love making this gratin when the weather turns cooler because it’s such a soothing, homey meal. One thing I’ve learned is to slice the vegetables evenly so they cook perfectly together and get that beautiful, slightly crispy top without the inside being undercooked. It’s easy to prepare ahead of time, too, which feels like a little win on busy days.
My favorite way to serve this dish is alongside a fresh green salad or some simple roasted chicken for a fulfilling dinner. It’s one of those recipes that tends to bring people together around the table, and I always get a few requests for seconds when I make it. Plus, it’s a great way to enjoy vegetables in a way that feels a little bit special and extra cozy.
Key Ingredients & Substitutions
Potatoes: Yukon Golds are great for a creamy texture, but Russets work well too for a fluffier bite. If you’re avoiding nightshades, try rutabaga or turnips instead.
Sweet Potatoes: They add a lovely sweetness and vibrant color. You can swap with butternut squash or pumpkin for a similar effect.
Beets: These bring earthiness and deep color. If you prefer a milder flavor, try using parsnips or carrots as alternatives.
Cheese: Gruyère melts beautifully and gives a nutty flavor. Parmesan is a nice sharper addition. For a dairy-free option, use a strong plant-based cheese or nutritional yeast.
Cream & Milk: The combo makes the sauce rich and smooth. For lighter options, use half-and-half or replace with oat or almond milk, though the texture will be a bit different.
How Do You Get Evenly Cooked, Perfectly Tender Vegetables?
Uniform slices are key. Use a sharp knife or mandoline to cut the veggies thin and even (about 1/8 inch). This helps them cook at the same rate and makes the gratin beautiful.
- Arrange slices upright or in overlapping layers for even baking and a nice presentation.
- Cover with foil during the first part of baking to trap steam and soften the vegetables.
- Finish uncovered to let the cheese brown and crisp on top.
- Let the dish rest a bit after baking so the sauce thickens and slices hold their shape.
Equipment You’ll Need
- Mandoline slicer – makes slicing vegetables thin and even much faster and safer.
- 9×13 inch baking dish – perfect size for layering the vegetables and baking evenly.
- Mixing bowl – for whisking the cream, milk, and cheese sauce smoothly.
- Whisk – helps blend ingredients without lumps for a creamy sauce.
- Aluminum foil – to cover the gratin while baking for tender vegetables and to avoid over-browning.
- Sharp chef’s knife – handy for trimming and slicing vegetables if you don’t have a mandoline.
Flavor Variations & Add-Ins
- Add cooked bacon or pancetta for smoky, salty bites that pair well with the sweet root vegetables.
- Mix in sautéed mushrooms for an earthy flavor and meaty texture, great if you want a fuller meal.
- Try swapping Gruyère for cheddar or fontina cheese for a milder or creamier cheesy topping.
- Sprinkle some fresh rosemary or sage instead of thyme for a woodsy, aromatic twist.
Cheesy Root Vegetable Gratin
Ingredients You’ll Need:
Vegetables:
- 2 medium potatoes (Yukon Gold or Russet), peeled and thinly sliced
- 2 medium sweet potatoes, peeled and thinly sliced
- 2 medium beets, peeled and thinly sliced
For The Creamy Sauce:
- 2 cups heavy cream
- 1 cup whole milk
- 2 garlic cloves, minced
- 1 ½ cups grated Gruyère cheese (or a mix of Gruyère and Parmesan)
- Salt and freshly ground black pepper to taste
- Optional: pinch of nutmeg
Other:
- 2 tablespoons unsalted butter (for greasing)
- Fresh thyme sprigs (about 2 tablespoons of leaves)
How Much Time Will You Need?
This recipe takes about 20 minutes to prep, including slicing and mixing. You’ll bake the gratin covered for 45 minutes, then uncovered for another 20 to 30 minutes until golden and tender. Allow 10 minutes resting time before serving. In total, plan around 1 hour and 15 minutes to make.
Step-by-Step Instructions:
1. Prepare the Baking Dish and Vegetables:
Preheat your oven to 375°F (190°C). Butter a 9×13 inch baking dish well to prevent sticking. Peel and thinly slice your potatoes, sweet potatoes, and beets evenly, about 1/8 inch thick, so they cook evenly and look neat in the gratin.
2. Make the Cream Sauce:
In a mixing bowl, whisk together heavy cream, whole milk, minced garlic, half of the grated cheese, salt (about 1 teaspoon), black pepper, and optional nutmeg. This will give your gratin a rich, flavorful sauce.
3. Assemble the Gratin:
Arrange the vegetable slices upright in rows or layered in the dish—potatoes on one side, sweet potatoes in the middle, beets on the other—to create a colorful and pretty combination. Pour the cream mixture evenly over the vegetables. Sprinkle the remaining grated cheese on top, then scatter fresh thyme leaves over everything.
4. Bake and Finish:
Cover the dish with foil and bake for 45 minutes to soften the vegetables. Then remove the foil and bake for an additional 20 to 30 minutes until the top is bubbling and nicely golden brown. The vegetables should be tender when pierced with a fork.
5. Rest and Serve:
Let the gratin rest for about 10 minutes after baking. This helps the sauce thicken slightly and allows easy serving. Enjoy this creamy, cheesy, and colorful gratin as a hearty side dish or a light main meal!
Can I Use Frozen Vegetables for This Gratin?
It’s best to use fresh vegetables for this recipe, as frozen root vegetables tend to release extra moisture and become mushy. If you must use frozen, thaw them completely and pat dry before slicing and assembling.
How Can I Make This Dish Ahead of Time?
You can assemble the gratin up to a day in advance, cover it tightly, and refrigerate. When ready to bake, remove it from the fridge 30 minutes before baking and then follow the baking steps as usual, adding a few extra minutes if needed.
What’s the Best Way to Store Leftovers?
Store any leftovers in an airtight container in the refrigerator for up to 3 days. Reheat gently in the oven at 350°F (175°C) until warmed through to keep the cheese sauce creamy and delicious.
Can I Substitute Different Cheeses?
Absolutely! Gruyère works wonderfully for its melting ability and flavor, but you can use cheddar, fontina, or a blend of Parmesan and mozzarella for different tastes and textures. Just make sure the cheese melts well.
