Name: Cheesy Root Vegetable Gratin Recipe
Prep time: 20 min
Cook time: 60 min
Total time: 80 min
Ingredients: 2 medium russet or Yukon Gold potatoes, peeled and thinly sliced; 2 medium sweet potatoes, peeled and thinly sliced; 2 large carrots, peeled and thinly sliced; 2 large parsnips, peeled and thinly sliced; 1 small red or yellow onion, very thinly sliced; 2 cloves garlic, minced or grated; 1 1/2 cups shredded Gruyère cheese; 1 cup shredded sharp cheddar cheese; 1/2 cup grated Parmesan cheese, divided; 2 cups heavy cream; 1/2 cup whole milk; 2 tablespoons unsalted butter; 1 1/2 teaspoons kosher salt, plus more to taste; 1/2 teaspoon black pepper; 1/2 teaspoon smoked or sweet paprika; 1/2 teaspoon dried thyme or 1 teaspoon fresh thyme leaves; 1 pinch nutmeg (optional); 1/2 cup panko or regular breadcrumbs; 1 tablespoon olive oil; 1 tablespoon chopped fresh parsley or chives, for garnish

Cheesy Root Vegetable Gratin Recipe tastes rich, creamy, and deeply savory, with crispy golden edges and tender layers of sweet root veggies. It works perfectly for cozy weeknights or holiday tables and takes about 1 hour 20 minutes from start to finish. I first baked a version of this on a tiny apartment oven rack that tilted to the left, so if I can pull it off, you absolutely can too.

Why Choose This Cheesy Root Vegetable Gratin Recipe

This gratin layers potatoes, sweet potatoes, parsnips, and carrots in a garlicky cream sauce with plenty of melty cheese. The mix of roots gives every bite a balance of sweetness, earthiness, and salty, cheesy goodness.

You slice everything thin, stack it in a baking dish, pour over a quick stovetop sauce, and let the oven handle the magic. The top turns bubbly and browned while the inside stays silky and spoonable.

“This Cheesy Root Vegetable Gratin Recipe stole the show at dinner and tasted even better the next day, which my family still talks about. ★★★★★”

Ingredients You’ll Need

Root vegetables

2 medium russet or Yukon Gold potatoes, peeled and thinly sliced
- Yukon Golds hold shape and taste buttery. Russets turn softer and extra creamy.
2 medium sweet potatoes, peeled and thinly sliced
2 large carrots, peeled and thinly sliced
2 parsnips, peeled and thinly sliced
1 small red onion or yellow onion, very thinly sliced
2 cloves garlic, minced or grated

You can swap parsnips for more carrots or use turnips or rutabaga if you like a stronger earthy flavor. Use a mandoline slicer or a sharp chef’s knife so the slices stay thin and even.

Cheese and dairy

1 ½ cups shredded Gruyère cheese
1 cup shredded sharp cheddar cheese
½ cup grated Parmesan cheese
2 cups heavy cream
½ cup whole milk
2 tablespoons unsalted butter

Use block cheese and shred it yourself so it melts smoothly. Pre-shredded cheese contains starch that can turn the sauce a bit grainy.

Seasonings

1 ½ teaspoons kosher salt, plus more to taste
½ teaspoon black pepper
½ teaspoon smoked paprika or sweet paprika
½ teaspoon dried thyme or 1 teaspoon fresh thyme leaves
Pinch of nutmeg (optional, but it adds a cozy flavor)

You can swap thyme for rosemary or Italian seasoning if that fits what you already have in the pantry.

Topping

½ cup panko breadcrumbs or regular breadcrumbs
1 tablespoon olive oil
2 tablespoons grated Parmesan cheese
1 tablespoon chopped fresh parsley or chives for garnish

Panko gives a lighter, crunchier topping. Regular breadcrumbs still taste great and brown nicely.

Equipment

9×13 inch baking dish or similar size casserole dish
Large mixing bowl
Medium saucepan
Whisk
Mandoline slicer or sharp chef’s knife
Cutting board
Aluminum foil

Tips & Tricks

Slice the vegetables very thin, about ⅛ inch, so they cook through at the same time.
Keep slices in separate piles by type, which helps you layer them in a pretty pattern.
Pat the sliced veggies dry with a clean towel to avoid extra water in the dish.
Warm the cream and milk on the stove so the gratin starts cooking faster in the oven.
Salt each layer lightly instead of dumping all the salt on top.
Mix cheeses together in a bowl before layering so the flavor spreads evenly.
Cover the dish with foil for the first part of baking so the veggies soften without burning the top.
Remove the foil near the end so the cheese browns and the topping turns crisp.
Let the gratin rest 10 to 15 minutes before serving so it sets and slices cleanly.
Use a rimmed baking sheet under the dish if it sits very full, since bubbly cheese can spill over.

How to Make Cheesy Root Vegetable Gratin Recipe

Prep the oven and pan

Heat the oven to 375°F.
Grease a 9×13 inch baking dish with butter or a little olive oil.
Set the dish aside while you slice the vegetables.

Slice the vegetables

Peel potatoes, sweet potatoes, carrots, and parsnips.
Slice them into thin rounds, about ⅛ inch thick, with a mandoline or sharp knife.
Slice the onion very thin and mince the garlic.
Keep each vegetable in its own pile so you can layer them easily.

Make the cheesy cream sauce

Add butter to a medium saucepan over medium heat and let it melt.
Add minced garlic and cook 30 to 45 seconds until fragrant, while you stir.
Pour in heavy cream and milk, then whisk in salt, pepper, paprika, thyme, and nutmeg.
Heat the mixture until it steams and tiny bubbles form around the edges, then turn off the heat.
Stir in half of the Gruyère, half of the cheddar, and 2 tablespoons Parmesan until they melt and the sauce looks smooth.

Layer the vegetables

Spread a thin layer of the cheesy cream sauce on the bottom of the baking dish.
Arrange a layer of mixed root vegetables and onion slices over the sauce. You can fan them in rows or tuck them in a shingled pattern.
Sprinkle a small handful of the remaining Gruyère and cheddar over the vegetables.
Spoon some of the cream sauce over that layer.
Repeat layers of vegetables, cheese, and sauce until you reach the top of the dish, finishing with sauce and a light sprinkle of cheese.

Add the crunchy topping

In a small bowl, mix panko breadcrumbs, olive oil, and 2 tablespoons grated Parmesan.
Stir until the crumbs look evenly coated and slightly glossy.
Sprinkle the breadcrumb mixture evenly over the top of the gratin.

Bake the gratin

Cover the dish loosely with foil, tenting it so it does not touch the cheese.
Bake 40 minutes, until the vegetables feel mostly tender when you poke them with a knife.
Remove the foil and bake another 20 to 25 minutes, until the top looks golden and the sauce bubbles around the edges.
If the top browns too quickly, lay the foil back on lightly and keep baking until the veggies finish cooking.

Rest and serve

Take the gratin out of the oven and place it on a cooling rack or trivet.
Let it rest 10 to 15 minutes so the sauce thickens slightly and the layers settle.
Sprinkle chopped parsley or chives over the top.
Slice into squares or scoop with a large spoon and serve warm.

What to Serve with it?

This Cheesy Root Vegetable Gratin Recipe pairs beautifully with simple roasted chicken thighs, baked salmon, or a skillet of garlicky shrimp. Add a crisp green salad with lemony vinaigrette to cut through the richness. Steamed green beans, roasted broccoli, or sautéed spinach also balance the creamy texture. For a cozy touch, serve it with a mug of hot cider or herbal tea.

Storage Options

Cool leftovers to room temperature, then cover the dish tightly or transfer slices to airtight containers and refrigerate for up to 4 days.
Freeze individual portions in freezer-safe containers or wrapped tightly in foil for up to 2 months.
Reheat in a 350°F oven, covered with foil, for 20 to 25 minutes from the fridge or 30 to 35 minutes from frozen, until hot in the center.
Use the microwave for quick single servings, then pop under the broiler for 1 to 2 minutes to crisp the top again.