Cheesy Root Vegetable Gratin is a comforting dish that brings together tender slices of root vegetables like potatoes, carrots, and parsnips, all baked in a creamy, cheesy sauce until golden and bubbly. The mix of sweet and earthy flavors from the veggies pairs perfectly with the rich cheese, making each bite warm and satisfying.
I love making this gratin when I want something hearty but not too heavy. The layers of veggies soak up the cheese sauce just right, and sometimes I add a little extra garlic or fresh herbs to give it a bit of a kick. It’s one of those dishes that feels special but is actually super easy to throw together, which I always appreciate on busy days.
My favorite way to serve this gratin is alongside a simple green salad or some roasted chicken. It’s the kind of dish everyone asks for seconds of because it feels like a cozy hug on a plate. Whenever I bake it, the smell filling the kitchen makes the whole house feel welcoming and ready for a good meal shared with friends or family.
Key Ingredients & Substitutions
Root Vegetables: Potatoes, sweet potatoes, parsnips, and beets each bring their unique flavor and texture. If you don’t have parsnips, turnips or rutabagas work well. For a different color, try purple potatoes.
Cream & Milk: Heavy cream gives richness, while milk lightens it up slightly. For a lighter gratin, use half-and-half or a plant-based milk like oat or cashew, but keep the cream for best results.
Cheese: Gruyère melts beautifully and adds a nutty flavor. Parmesan adds sharpness if mixed in. You can swap Gruyère with Fontina, Emmental, or aged cheddar if needed.
Fresh Thyme: Adds a subtle earthy fragrance. If fresh isn’t available, dried thyme works too but use less as it’s more concentrated.
How Do I Get Perfectly Cooked and Crispy-Topped Gratin?
The key is layering thin slices evenly so everything cooks through and the cream sauce seeps in well. Use a sharp knife or mandoline for uniform slices.
- Preheat the cream mixture to help the layers cook evenly and keep the sauce smooth.
- Cover the dish with foil while baking to trap steam and soften the veggies.
- Remove foil near the end to brown the cheese. Keep an eye to avoid burning.
- Let the gratin rest after baking so it thickens up enough for neat slices.
These steps lead to tender vegetables with a bubbly, golden crust that’s both tasty and visually appealing.
Equipment You’ll Need
- Sharp chef’s knife – makes slicing root vegetables thin and even, which helps them cook perfectly.
- Mandoline slicer – if you have one, it speeds up slicing and ensures uniform thickness every time.
- Medium saucepan – to gently heat the cream, milk, garlic, and thyme without boiling.
- 2-quart baking dish – roomy enough for layering the vegetables and cheese; a ceramic or glass dish works great.
- Aluminum foil – used to cover the dish to trap moisture while baking, preventing the veggies from drying out.
Flavor Variations & Add-Ins
- Add cooked, crumbled bacon or pancetta for a salty, smoky touch that pairs well with the creamy cheese sauce.
- Mix in chopped fresh rosemary or sage instead of thyme for a different earthy herbal flavor.
- Include sliced mushrooms or sautéed leeks for extra texture and a mild oniony taste.
- Try swapping Gruyère for sharp cheddar or mozzarella for a milder or stretchier cheese experience.
Cheesy Root Vegetable Gratin
Ingredients You’ll Need:
Vegetables:
- 2 medium potatoes, peeled and thinly sliced
- 2 medium sweet potatoes, peeled and thinly sliced
- 2 medium parsnips, peeled and thinly sliced
- 1 medium beetroot, peeled and thinly sliced
Cheese Sauce:
- 3 cloves garlic, minced
- 2 cups heavy cream
- 1 cup whole milk
- 1 ½ cups grated Gruyère cheese (or a mix of Gruyère and Parmesan)
- 2 teaspoons fresh thyme leaves, plus extra for garnish
- Salt and freshly ground black pepper, to taste
- 2 tablespoons unsalted butter, for greasing the dish
How Much Time Will You Need?
This recipe takes about 15-20 minutes to prepare and around 1 hour to bake. Including resting time, you should set aside roughly 1 hour and 30 minutes from start to finish.
Step-by-Step Instructions:
1. Get Ready:
Preheat your oven to 375°F (190°C). Butter a medium-sized baking dish generously to prevent sticking and add flavor.
2. Prepare the Cream Mixture:
In a saucepan, gently heat the heavy cream, milk, minced garlic, and fresh thyme over medium-low heat until just about to simmer. Be careful not to boil. Remove from heat once it’s hot and aromatic.
3. Layer the Vegetables:
Arrange the thinly sliced potatoes, sweet potatoes, parsnips, and beetroot in your baking dish. Place them in overlapping rows or circles, alternating vegetable types to create a colorful and attractive pattern. Lightly season each layer with salt and pepper as you go.
4. Add Cream and Cheese:
Pour the warm cream mixture over the arranged vegetables, making sure it seeps down between the slices. Then sprinkle the grated Gruyère cheese evenly over the top.
5. Bake Covered:
Cover the baking dish tightly with aluminum foil and bake for 40 minutes. This helps the vegetables soften evenly without drying out.
6. Bake Uncovered:
Remove the foil and continue baking for another 25-30 minutes, or until the top is beautifully golden brown and the vegetables are tender when poked with a fork.
7. Rest and Serve:
Take the gratin out of the oven and let it rest for at least 10 minutes. This allows the cheesy sauce to set a little, making it easier to serve. Sprinkle with fresh thyme leaves for garnish before serving warm.
Enjoy your delicious, creamy, cheesy root vegetable gratin that’s perfect for cozy meals!
Can I Use Frozen or Pre-Cut Vegetables?
Frozen or pre-cut vegetables can be used in a pinch, but fresh, thinly sliced vegetables yield the best texture and flavor. If using frozen, thaw and pat them dry to avoid excess moisture that can make the gratin watery.
Can I Make This Gratin Ahead of Time?
Yes! Assemble the gratin up to step 5, then cover and refrigerate for up to 24 hours before baking. When ready, bake covered, then uncovered as directed, adding a few extra minutes if needed for thorough cooking.
What’s the Best Way to Store Leftovers?
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 or milk to refresh the sauce if it’s thickened too much.
Can I Substitute the Cheese?
Definitely! Gruyère is ideal for its meltability and flavor, but you can use Fontina, Emmental, cheddar, or a similar melting cheese. Mixing cheeses can add extra flavor complexity too.
