Cheesy Root Vegetable Gratin is a cozy, comforting dish that brings together tender slices of root veggies like potatoes, carrots, and parsnips all layered with melted cheese and a creamy sauce. It’s golden and bubbly on top with just the right amount of crispiness around the edges, making it a perfect side or even a main for chilly days.
I love making this dish when I want something hearty but still packed with fresh, natural flavors from the veggies. What makes it extra special for me is the mix of cheeses I use—it gives the gratin a rich, gooey texture that everyone always asks for seconds. Plus, it has this homey, slightly sweet taste from the root veggies that I think pairs beautifully with the savory cheese.
One of my favorite ways to serve this is alongside roast chicken or a simple green salad. It’s a crowd-pleaser at family dinners and holidays, and leftovers reheat really well the next day. If you’re trying it for the first time, I’d recommend slicing the vegetables as evenly as possible so everything cooks perfectly together. It’s a warm embrace on a plate, and I guarantee it’ll be a new favorite in your kitchen!
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Key Ingredients & Substitutions
Beets and Root Vegetables: These give the gratin its color and earthy, sweet flavors. If you can’t find beets, try turnips or rutabaga. Make sure to slice all veggies evenly so they cook together well.
Heavy Cream and Milk: Heavy cream makes the sauce rich and silky. For a lighter option, swap for half-and-half or use all milk with a bit of butter added.
Gruyère Cheese: It melts beautifully and adds a nutty flavor. You can substitute with Swiss, Fontina, or even a sharp cheddar if needed. Parmesan on top boosts the crust’s crispiness.
Thyme & Garlic: These add fresh, aromatic notes that balance the richness. If fresh thyme isn’t available, dried thyme works fine but use less since it is stronger.
How Can I Get Evenly Cooked, Creamy Vegetables in a Gratin?
Slicing vegetables thinly and evenly is key to ensure they all cook at the same rate.
- Use a mandoline or a very sharp knife for consistent slices around 1/8-inch thick.
- Layer the veggies tightly but don’t overcrowd. Overlapping slightly helps everything cook evenly while soaking up the sauce.
- Warm the cream sauce before pouring it over to jump-start cooking inside the oven.
- Cover with foil for most of the baking time to trap steam and gently cook the veggies, then remove foil at the end to let the top brown.
These steps help you get tender, flavorful veggies with a golden cheese crust every time.
Equipment You’ll Need
- Mandoline slicer – makes thin, even slices of root vegetables fast and safe.
- Medium saucepan – for warming the cream sauce evenly without boiling.
- Oven-safe gratin dish – a ceramic or glass dish lets you layer veggies and bake evenly.
- Sharp knife – handy if you don’t have a mandoline for slicing vegetables neatly.
- Aluminum foil – covers the dish while baking to keep moisture in and veggies tender.
Flavor Variations & Add-Ins
- Add cooked crumbled sausage or bacon for a smoky, meaty boost that complements the creamy cheese.
- Mix in grated sharp cheddar or aged Parmesan to up the tang and create a stronger cheese crust.
- Include sautéed mushrooms or wilted spinach layers for extra earthiness and texture.
- Season with a pinch of nutmeg or smoked paprika to give the gratin a subtle warm spice kick.
Cheesy Root Vegetable Gratin
Ingredients You’ll Need:
Vegetables:
- 2 medium beets, peeled and thinly sliced
- 2 medium golden potatoes, peeled and thinly sliced
- 2 medium sweet potatoes, peeled and thinly sliced
- 2 medium carrots, peeled and thinly sliced
Sauce & Toppings:
- 2 cups heavy cream
- 1 cup whole milk
- 2 cups grated Gruyère cheese (or a mix of Gruyère and Parmesan)
- 2 garlic cloves, minced
- 1 tsp fresh thyme leaves, plus extra for garnish
- Salt and freshly ground black pepper to taste
- 2 tbsp unsalted butter (for greasing the baking dish)
- Optional: pinch of nutmeg
How Much Time Will You Need?
This recipe takes about 20 minutes to prepare (including peeling and slicing the vegetables), plus 1 hour and 15 minutes of baking time. You’ll want to let the gratin rest for 10 minutes before serving to get that delicious creamy texture settled. In total, plan for roughly 1 hour and 35 minutes from start to table.
Step-by-Step Instructions:
1. Preparing the Baking Dish and Cream Sauce:
Start by preheating your oven to 375°F (190°C). Generously butter a medium-sized oval or rectangular gratin dish to prevent sticking and help crisp the edges. In a saucepan, combine the heavy cream, milk, minced garlic, thyme leaves, salt, pepper, and a pinch of nutmeg if you like. Warm this mixture over low heat just until it begins to simmer, then remove it from the heat.
2. Arranging the Vegetables:
Slice the beets, golden potatoes, sweet potatoes, and carrots evenly into thin rounds—about 1/8 inch thick works well. Arrange them in the prepared dish in neat rows or concentric circles, overlapping the slices slightly. Alternate the root vegetables to create a colorful, pretty pattern just like in the photo.
3. Assembling and Baking the Gratin:
Pour the warm cream sauce evenly over the arranged vegetables, making sure it seeps through all layers. Sprinkle 1 ½ cups of the grated Gruyère cheese evenly across the top. Cover the dish loosely with aluminum foil and bake for about 45 minutes. Then, remove the foil, sprinkle the remaining ½ cup of cheese on top, and bake uncovered for another 20 to 30 minutes—or until the top is golden and bubbly and the vegetables are tender when poked with a fork.
4. Final Touches and Serving:
Once baked, let your gratin rest for 10 minutes so the sauce thickens slightly and everything settles nicely. Garnish with some fresh thyme leaves if you like, then serve it warm. This dish is wonderful as a comforting side or a main for a cozy meal.
Can I Use Frozen Root Vegetables for the Gratin?
Yes, you can use frozen vegetables, but be sure to thaw them completely and pat dry to avoid excess water in the dish. Thaw in the fridge overnight or use cold water for quicker thawing.
How Should I Store Leftover Gratin?
Store leftovers in an airtight container in the refrigerator for up to 3 days. Reheat gently in the oven or microwave until warmed through, adding a splash of cream if needed to keep it creamy.
Can I Make This Dish Ahead of Time?
Absolutely! Assemble the gratin and refrigerate it covered for up to 24 hours before baking. When ready, bake as directed, but you might need to add a few extra minutes to baking time if starting from cold.
What Are Good Substitutes for Gruyère Cheese?
Gruyère adds a nutty creaminess, but you can substitute Swiss cheese, Fontina, or sharp cheddar. Mixing in Parmesan on top helps create a nice golden crust as well.
