I like how this gratin layers thinly sliced vegetables with a luscious cheese sauce that melts into every bite. The blend of cheddar and Parmesan creates the perfect balance of sharp and nutty flavors. It’s hearty, visually stunning, and pairs beautifully with roasted meats or served as a vegetarian main. Plus, it’s an easy make-ahead dish that reheats beautifully, which makes it ideal for entertaining.
Ingredients
(Note: All ingredient amounts are listed in the recipe card below.)
2 pounds (about 900g) mixed root vegetables (such as potatoes, sweet potatoes, parsnips, and carrots), peeled and thinly sliced 1 small onion, thinly sliced 2 cloves garlic, minced 2 tablespoons butter 2 tablespoons all-purpose flour 2 cups milk (whole milk or 2%) 1 1/2 cups shredded sharp cheddar cheese 1/2 cup grated Parmesan cheese Salt and black pepper to taste 1/4 teaspoon ground nutmeg (optional) Fresh thyme leaves for garnish (optional)
Directions
I start by preheating the oven to 375°F (190°C) and greasing a 9×13-inch baking dish with butter or cooking spray. Then I peel and thinly slice my root vegetables—using a mandoline makes this step easy and ensures even cooking.
In a medium saucepan, I melt the butter over medium heat and sauté the sliced onion and minced garlic for about 3–4 minutes until fragrant and soft. I sprinkle in the flour and stir constantly for about 1–2 minutes to form a roux. Slowly, I pour in the milk while whisking to avoid lumps, then cook until the sauce thickens, about 5–7 minutes.
Once thickened, I reduce the heat and stir in 1 cup of cheddar cheese and 1/4 cup of Parmesan cheese until smooth. I season the sauce with salt, pepper, and nutmeg. Then I pour the sauce over the sliced vegetables in a large bowl and toss gently to coat everything evenly.
I arrange the coated vegetables in the prepared baking dish, cover with foil, and bake for about 35–40 minutes until the vegetables are tender when pierced with a fork. After that, I remove the foil and sprinkle the remaining 1/2 cup cheddar and 1/4 cup Parmesan on top. I return the dish to the oven, uncovered, and bake for another 15–20 minutes until the top is golden and bubbling.
Once baked, I let the gratin cool for a few minutes before serving, garnishing it with fresh thyme leaves for a beautiful finishing touch.
Servings and Timing
This recipe serves about 6–8 people. It takes around 20 minutes of prep time and 55–60 minutes of cook time, for a total of roughly 1 hour and 20 minutes.
Variations
I sometimes switch up the cheese, using Gruyère for a nutty flavor or mozzarella for a more gooey texture. When I want to add a smoky note, I use smoked cheddar between layers. For a lighter version, I use half-and-half instead of full milk and reduce the cheese slightly. If I want an extra crisp topping, I mix breadcrumbs with Parmesan and butter before sprinkling it over the top.
Storage/Reheating
I like to store leftover gratin in an airtight container in the refrigerator for up to 3 days. To reheat, I cover it with foil and warm it in a 350°F oven for about 15–20 minutes, or until heated through. If I’m reheating a single portion, I use the microwave for about 1–2 minutes, though the oven keeps the texture crispier. This dish also freezes well—just cool it completely, wrap tightly, and freeze for up to 2 months. I thaw it overnight in the fridge before reheating.
FAQs
Can I make this gratin ahead of time?
Yes, I assemble the dish up to a day in advance, cover it tightly, and refrigerate it. When ready to serve, I bake it as directed.
What are the best vegetables to use?
I like mixing potatoes, sweet potatoes, carrots, and parsnips for flavor and color contrast, but turnips or rutabagas also work great.
Can I use heavy cream instead of milk?
Yes, heavy cream will make the sauce even richer and creamier.
How do I get the top extra crispy?
I broil the gratin for 1–2 minutes after baking, watching closely to prevent burning.
Can I make it gluten-free?
I replace the flour with cornstarch or a gluten-free all-purpose blend to thicken the sauce.
What cheese substitutes work best?
Gruyère, fontina, or Monterey Jack are great alternatives to cheddar.
How can I make this dish vegan?
I use plant-based milk, vegan butter, and a dairy-free cheese alternative to make it vegan-friendly.
Can I slice the vegetables ahead of time?
Yes, I slice them up to 6 hours in advance and store them in cold water to prevent browning, then drain and pat dry before baking.
What can I serve this gratin with?
I love pairing it with roasted chicken, beef, or a fresh green salad—it complements just about any main dish.
Conclusion
I love how this Cheesy Root Vegetable Gratin transforms humble vegetables into something truly elegant and comforting. The creamy sauce, gooey cheese, and tender layers make it a side dish that always impresses. Whether for a holiday feast or a simple weeknight dinner, this recipe brings warmth, richness, and a touch of sophistication to the table every time.
This Cheesy Root Vegetable Gratin combines tender layers of potatoes, parsnips, carrots, and sweet potatoes with a rich, creamy cheese sauce. Golden, bubbly, and comforting, it’s the perfect side dish for holidays or cozy dinners.
Ingredients
2 pounds (about 900g) mixed root vegetables (potatoes, sweet potatoes, parsnips, and carrots), peeled and thinly sliced
1 small onion, thinly sliced
2 cloves garlic, minced
2 tablespoons butter
2 tablespoons all-purpose flour
2 cups milk (whole or 2%)
1 1/2 cups shredded sharp cheddar cheese
1/2 cup grated Parmesan cheese
Salt and black pepper to taste
1/4 teaspoon ground nutmeg (optional)
Fresh thyme leaves, for garnish (optional)
Instructions
Preheat oven to 375°F (190°C) and grease a 9×13-inch baking dish with butter or cooking spray.
Peel and thinly slice all root vegetables using a mandoline for even thickness.
In a medium saucepan, melt butter over medium heat. Add onion and garlic and sauté for 3–4 minutes until fragrant and soft.
Stir in flour to form a roux, cooking for 1–2 minutes while stirring constantly.
Gradually whisk in milk until smooth and thickened, about 5–7 minutes.
Reduce heat and stir in 1 cup cheddar and 1/4 cup Parmesan cheese until melted. Season with salt, pepper, and nutmeg if using.
In a large bowl, toss sliced vegetables with the cheese sauce until evenly coated.
Spread the mixture evenly in the prepared baking dish, cover with foil, and bake for 35–40 minutes or until vegetables are tender.
Remove foil, sprinkle remaining 1/2 cup cheddar and 1/4 cup Parmesan over the top, and bake uncovered for 15–20 minutes more until golden and bubbly.
Let cool slightly before serving and garnish with fresh thyme.
Notes
Use Gruyère, fontina, or mozzarella instead of cheddar for a different flavor.
Add crumbled bacon or cooked ham between layers for extra heartiness.
Top with breadcrumbs mixed with Parmesan and butter for a crispier finish.
Make ahead by assembling up to one day early, then refrigerating before baking.
For a gluten-free version, replace flour with cornstarch or a GF flour blend.
Store leftovers up to 3 days in the fridge or freeze up to 2 months.
