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Cheesy Root Veggie Gratin is a cozy, layered casserole that celebrates the sweet, earthy flavors of winter root vegetables under a lusciously cheesy sauce. Friendly and comforting, this gratin makes a stunning centerpiece for holiday meals or an indulgent weeknight side that feeds a crowd. If you enjoy rich, savory bakes, you’ll find it both satisfying and surprisingly simple — and if you liked my take on a cheesy chicken wrap, you’ll appreciate the same attention to creamy, melty texture here.

Why make this recipe

It turns inexpensive root vegetables into a showstopping, elegant side dish.
The combination of Gruyère, sharp cheddar, and Parmesan creates a deeply savory, nutty sauce that complements sweet potatoes and parsnips beautifully.
This gratin is also a practical make-ahead dish that reheats well, so it’s perfect for entertaining or easing holiday kitchen stress.

Step-by-Step Guide to Making Cheesy Root Veggie Gratin

Prepare Root Vegetables

Preheat your oven to 375°F (190°C). Butter a 9×13 inch baking dish thoroughly so the gratin won’t stick and the edges brown evenly.
Peel all root vegetables: 2 large Russet or Yukon Gold potatoes (about 1.5 lbs), 2 medium sweet potatoes (about 1.25 lbs), 3 medium carrots (about 0.75 lbs), 2 medium parsnips (about 0.5 lbs), and 1 small celeriac (optional, about 0.5 lbs). For best texture, use a mandoline or a very sharp knife to slice every vegetable about 1/8-inch thick; uniform thickness ensures even cooking.
Place the slices in a large bowl, drizzle with 1 tablespoon olive oil or melted butter, sprinkle 1 teaspoon fresh thyme leaves, 1/2 teaspoon salt, and 1/4 teaspoon black pepper, then toss gently to coat. This light seasoning before layering gives each slice a little base flavor.

Craft Creamy Cheese Sauce
4. In a large saucepan or Dutch oven, melt 4 tablespoons unsalted butter over medium heat. Add 2 cloves minced garlic and 1 small finely minced shallot (or 1/4 small onion). Sauté for 2–3 minutes until fragrant and softened but not browned.
5. Sprinkle in 4 tablespoons all-purpose flour and whisk continuously for 1–2 minutes to form a blonde roux — this cooks the raw flour taste and thickens the sauce later.
6. Slowly whisk in 4 cups warmed whole milk and 1 cup warmed heavy cream, a little at a time if you like, to avoid lumps. Simmer gently for 5–7 minutes, whisking until the sauce thickens and coats the back of a spoon.
7. Remove from heat, then stir in 1/2 teaspoon freshly grated nutmeg, 1 teaspoon salt, and 1/2 teaspoon white pepper for a subtle, warm note.
8. Add 1.5 cups grated Gruyère, 0.75 cups grated sharp white cheddar, and 0.25 cups grated Parmesan to the sauce. Stir gently until the cheese melts and the sauce becomes smooth and velvety. Taste and adjust seasoning.

Assemble the Gratin Layers
9. Spread a thin layer of the creamy cheese sauce on the bottom of the buttered baking dish to prevent sticking and create a flavor base.
10. Arrange a single, even layer of sliced root vegetables over the sauce — alternate potato, sweet potato, parsnip, and carrot slices for color and flavor contrast when possible.
11. Ladle a generous amount of sauce over the vegetable layer, then sprinkle a small amount of the remaining grated cheeses (Gruyère, cheddar, and Parmesan).
12. Repeat layering: vegetables, sauce, sprinkle of cheese, pressing lightly on each layer so the gratin holds together. Finish with a final layer of sauce covering the top completely.

Prepare Optional Topping (if desired)
13. For a crunchy topping, combine 1/2 cup panko breadcrumbs with 2 tablespoons melted butter in a small bowl and toss until coated. Sprinkle evenly over the top of the gratin.
14. If you prefer not to use breadcrumbs, cover the top generously with the remaining reserved grated cheeses for a deeply browned, cheesy crust.

Bake Covered
15. Cover the baking dish tightly with aluminum foil and bake at 375°F (190°C) for 45 minutes. The covered bake steams the layers, ensuring the thicker root vegetables cook through without drying.

Bake Uncovered to Golden Perfection
16. Carefully remove the foil. Increase the oven temperature to 400°F (200°C) for faster browning (or keep at 375°F/190°C if you want slower, even browning). Return the uncovered gratin and bake for an additional 25–35 minutes, or until the top is deeply golden brown, bubbling, and a thin knife inserted into the center meets little resistance.

Rest Before Serving
17. Remove the gratin from the oven and let it rest undisturbed on a wire rack for at least 15–20 minutes. Resting allows the sauce to set and the layered slices to firm up for clean, attractive slices.
18. Garnish with extra fresh thyme sprigs before slicing and serving.

Notes on timing and small technique points

Slicing evenly is the most important step: if you don’t have a mandoline, use a sharp knife and take your time. Slight differences in thickness are okay but large variations will affect cook time.
Warming the milk and cream helps the sauce come together smoothly and reduces the time it spends on heat, preventing overcooking.
If your sauce looks a touch thin after assembly, don’t worry — it will thicken as it bakes and rests.

Keeping Cheesy Root Veggie Gratin Fresh

Refrigerator: Store in an airtight container or tightly covered dish at 35–40°F (2–4°C) for 3–4 days.
Freezer: Wrap tightly in plastic wrap then foil, or use a freezer-safe container; freeze for up to 2 months. Thaw overnight in the refrigerator before reheating.
Reheating: Reheat individual portions in a 350°F (175°C) oven for 10–15 minutes (covered) or until warmed through; for a crisp top, uncover for the last 5 minutes.

Serving Suggestions for Cheesy Root Veggie Gratin

Holiday centerpiece: Serve slices alongside roast turkey or glazed ham and a bright green salad to balance the richness.
Weeknight comfort: Pair with roasted chicken thighs or a simple pan-seared salmon and a handful of steamed green beans tossed with lemon.
Vegetarian meal: Make it the main event with a crisp mixed greens salad, warm crusty bread, and a tart apple-cider vinaigrette to cut through the creaminess.
Plating tip: Slice the gratin into neat squares with a sharp knife and a spatula; a quick pass under the broiler (watch closely) will re-crisp any softened top before serving.

Tips to Make Cheesy Root Veggie Gratin
Q: How do I keep the gratin from getting watery?
A: Make sure to dry potato and sweet potato slices if they’re wet after peeling; also avoid over-thinning the sauce — it should coat the back of a spoon before assembly.

Q: Can I make this ahead?
A: Yes — assemble the gratin up to the point of baking, cover tightly, and refrigerate for up to 24 hours. Remove from the fridge while the oven preheats and bake as directed (you may need to add 10–15 minutes to the covered bake time).

Q: How do I get a golden, bubbly top?
A: Use the uncovered baking step at a higher temperature (400°F/200°C) and finish with a couple minutes under the broiler if necessary, watching closely to avoid burning.

Variations and Substitutions

Cheese swap: Replace Gruyère with Emmental or fontina for a milder nutty note, or use smoked cheddar for a deeper flavor. (Note: cheese substitutions will change melting characteristics; choose one with good melting properties.)
Gluten-free version: Substitute a 1:1 gluten-free flour blend in the roux and use gluten-free panko for the topping.
Dairy-light option: Use half-and-half in place of heavy cream and reduce the amount slightly, but expect a slightly less rich sauce; you can thicken with a touch more roux if needed.

Cooking equipment you’ll find helpful

Mandoline slicer for ultra-thin, consistent slices.
Large, heavy-bottomed saucepan or Dutch oven for making the sauce.
A 9×13 inch baking dish (glass or ceramic both work) for even baking.
Microplane for grating nutmeg and cheeses for best melting and texture.

Troubleshooting

Sauce too thin after assembly: If you notice during the covered bake that the sauce seems thin, leave the foil off for a longer time during the final bake to allow excess moisture to evaporate and the sauce to reduce.
Top browning too fast: Tent with foil during the last 10–15 minutes if the top is getting too dark before the center is tender.
Vegetables not tender: Ensure slices are about 1/8-inch thick; if slices are thicker, increase the initial covered bake by 10–15 minutes.

FAQs
Q: Can I use only potatoes and sweet potatoes?
A: Yes. If you prefer a simpler mix, a potato + sweet potato combination still gives great texture and flavor. The parsnips and carrots add complexity and sweetness, but they’re not essential.

Q: How can I make this less rich without losing flavor?
A: Reduce the heavy cream to 1/2 cup and substitute extra milk, and use a stronger-flavored cheese like sharp cheddar or aged Gruyère to maintain savory depth.

Q: Is there a vegan version?
A: For a vegan adaptation, make a plant-based béchamel with olive oil or vegan butter, flour, and unsweetened soy or oat milk, and use dairy-free shredded cheeses that melt well; add nutritional yeast for savory umami.

Bold question style:
What’s the best way to slice the root vegetables?
Use a mandoline set to about 1/8-inch for the most even slices; if using a knife, try to keep each slice as consistent as possible and accept that slightly varied slices will still work.

Do I need to peel everything?
For visual and textural uniformity, peeling is recommended, especially for sweet potatoes, parsnips, and celeriac. If your Yukon Gold potatoes have thin skins you prefer to keep, they can be left on if scrubbed clean.

How to adapt for higher altitude?
Increase baking time slightly and monitor doneness by probing the center with a knife. You may need an additional 10–20 minutes for the covered bake stage.

Variation (comparison-style)

Classic vs. Herb-forward: Classic uses the thyme in the recipe and nutmeg in the sauce; an herb-forward version doubles the thyme and adds a tablespoon of finely chopped rosemary for a piney lift.
Cheese-forward vs. Light-cheese: Cheese-forward increases the Gruyère by 1/2 cup for a richer, gooier finish; light-cheese reduces cheddar and Gruyère by 25% and adds 1/4 cup grated Parmesan for stronger flavor with less volume.

Final plating and presentation ideas

For an elegant holiday table, cut the gratin into squares and arrange them on a warmed platter garnished with whole thyme sprigs and a few lemon-zested microgreens for brightness.
For family-style service, place the baking dish on a trivet in the center of the table with a serving spatula, letting guests scoop their portions.

A few final chef’s notes

Quality of cheese matters: freshly grated cheese melts more smoothly and yields a better texture than pre-grated packets that often contain anti-caking agents.
Rotate vegetables: the sweeter vegetables (sweet potato, carrot) can be layered so they’re spread evenly rather than clumped, which gives more balanced flavor in each bite.
Don’t rush the rest: resting the gratin is not optional if you want clean slices. If you’re impatient, at least wait 10 minutes, but 15–20 is ideal.

Conclusion

For an inspiring reference and variations on cheesy root bakes, see Spoon Fork Bacon’s Cheesy Root Vegetable Gratin, which showcases another delicious interpretation. If you’re looking for orchard-inspired takes and seasonal pairing ideas, explore Weavers Orchard’s Root Vegetable Gratin for helpful inspiration and serving suggestions.

Cheesy Root Veggie Gratin

Author: admin
Total Time: 100 minutes
Yield: 8 servings 1x
Diet: Vegetarian

Print Recipe

Description

A cozy, layered casserole of winter root vegetables under a cheesy sauce, perfect for holiday meals or as a comforting side dish.

Ingredients

Scale

2 large Russet or Yukon Gold potatoes (about 1.5 lbs)
2 medium sweet potatoes (about 1.25 lbs)
3 medium carrots (about 0.75 lbs)
2 medium parsnips (about 0.5 lbs)
1 small celeriac (optional, about 0.5 lbs)
1 tablespoon olive oil or melted butter
1 teaspoon fresh thyme leaves
1/2 teaspoon salt
1/4 teaspoon black pepper
4 tablespoons unsalted butter (for sauce)
2 cloves minced garlic
1 small finely minced shallot (or 1/4 small onion)
4 tablespoons all-purpose flour
4 cups warmed whole milk
1 cup warmed heavy cream
1/2 teaspoon freshly grated nutmeg
1 teaspoon salt (for sauce)
1/2 teaspoon white pepper
1.5 cups grated Gruyère cheese
0.75 cups grated sharp white cheddar cheese
0.25 cups grated Parmesan cheese
1/2 cup panko breadcrumbs (optional topping)
2 tablespoons melted butter (for topping)

Instructions

Preheat your oven to 375°F (190°C) and butter a 9×13 inch baking dish.
Peel root vegetables and slice them thinly (about 1/8-inch thick).
In a bowl, drizzle sliced vegetables with olive oil, thyme, salt, and pepper; toss to coat.
In a saucepan, melt butter and sauté garlic and shallot for 2-3 minutes.
Sprinkle flour, whisk to form a roux, then gradually whisk in warm milk and cream.
Simmer sauce for 5-7 minutes until thickened, then stir in nutmeg, salt, white pepper, and cheeses until melted.
Spread a layer of cheese sauce in the baking dish, then layer root vegetables and more sauce, repeating layers.
If desired, mix breadcrumbs with melted butter and sprinkle on top, or use remaining cheeses.
Cover with foil and bake for 45 minutes, then uncover and increase temperature to 400°F (200°C) and bake for another 25-35 minutes until golden brown.
Let cool for 15-20 minutes before serving and garnish with fresh thyme.

Notes

Store leftovers in an airtight container for 3-4 days or freeze for up to 2 months. Reheat at 350°F (175°C).

Prep Time: 30 minutes
Cook Time: 70 minutes
Category: Side Dish
Method: Baking
Cuisine: American

Nutrition

Serving Size: 1 serving
Calories: 400
Sugar: 6g
Sodium: 500mg
Fat: 18g
Saturated Fat: 10g
Unsaturated Fat: 6g
Trans Fat: 0g
Carbohydrates: 50g
Fiber: 4g
Protein: 12g
Cholesterol: 60mg

Keywords: gratin, root vegetables, cheesy, vegetarian, casserole

Cheesy Root Veggie Gratin

Conclusion