Cheesy Root Vegetable Gratin is a warm and comforting dish that highlights the natural sweetness of root veggies like carrots, parsnips, and potatoes, all baked to tender perfection under a bubbly, golden layer of melted cheese. The creamy sauce brings everything together, making every bite rich without being too heavy.
I love making this gratin when I want something hearty but still a bit special on the table. It’s one of those dishes that feels like a cozy hug, especially on chilly days. I find that using a mix of your favorite seasonal root vegetables adds great flavor and texture, and the cheese topping gets everyone excited even before it comes out of the oven.
My favorite way to serve this is alongside some simple roasted chicken or a fresh green salad—enough to balance out the richness but still keep the meal satisfying. It’s also a great dish to bring to family dinners because it’s easy to make ahead and always disappears quickly. If you’re looking for comfort food that’s a little different, this cheesy root vegetable gratin definitely hits the spot!
Key Ingredients & Substitutions
Root vegetables: Potatoes, sweet potatoes, parsnips, and turnips make this dish tasty and colorful. Feel free to swap turnips for rutabaga or add beets for extra sweetness and color.
Cream and milk: Mixing cream and milk keeps the sauce rich but not too heavy. For a lighter version, try using half-and-half or even whole milk alone.
Cheese: Gruyère brings a nice nutty flavor and melts well. If you don’t have Gruyère, cheddar or Swiss cheese work nicely, or a combo of both.
Herbs & spices: Fresh thyme and nutmeg add subtle warmth. If fresh thyme isn’t available, dried thyme is fine, just use a bit less.
How Do I Get the Vegetables Thin and Cooked Perfectly?
Thin, even slicing is crucial so everything cooks evenly and layers nicely.
- Use a sharp knife or a mandoline slicer to get uniform ⅛-inch thick slices.
- Layer the vegetables tightly but not packed too hard to let the cream soak through.
- Covering the dish while baking keeps moisture in and helps cook the veggies thoroughly.
- After removing foil, baking uncovered lets the cheese brown and crisp up beautifully.
Letting the gratin rest after baking helps the sauce set a bit, making it easier to slice and serve. This dish tastes best when it’s had time to cool down slightly but is still warm.
Equipment You’ll Need
- Mandoline slicer or sharp knife – I recommend a mandoline for even slices and quick prep.
- Medium saucepan – to warm the cream mixture, keeping it flavorful and smooth.
- Large baking dish or gratin dish – a medium-sized oval or rectangular dish works well to hold all the layers.
- Pastry brush or spoon – for spreading the cream mixture evenly over the vegetables.
- Aluminum foil – helps keep the dish moist and prevents the cheese from burning during the initial baking stage.
Flavor Variations & Add-Ins
- Swap Gruyère for sharp cheddar or Parmesan for a different cheese flavor profile.
- Add cooked bacon, pancetta, or ham between layers for extra richness and saltiness.
- Mix in sautéed onions or garlic with the vegetables for more depth.
- Include fresh herbs like rosemary or sage along with thyme for a change in aroma and flavor.
Cheesy Root Vegetable Gratin
Ingredients You’ll Need:
Vegetables:
- 2 medium potatoes, peeled and thinly sliced
- 2 medium sweet potatoes or yams, peeled and thinly sliced
- 2 medium parsnips, peeled and thinly sliced
- 1 medium turnip, peeled and thinly sliced (optional)
For The Cream Sauce:
- 2 cups heavy cream
- 1 cup whole milk
- 2 cloves garlic, minced
- 1 tsp fresh thyme leaves, plus extra for garnish
- ½ tsp freshly grated nutmeg
- Salt and freshly ground black pepper to taste
Cheese & Extras:
- 2 cups grated Gruyère cheese (or a mix of Gruyère and cheddar)
- 2 tbsp unsalted butter (for greasing the baking dish)
How Much Time Will You Need?
This dish takes about 20 minutes to prep, with about 1 hour to bake, including time covered with foil and uncovered to brown. Let it rest 10 minutes before serving. Plan for a total of roughly 1 hour 30 minutes from start to finish.
Step-by-Step Instructions:
1. Prepare the Oven and Dish:
Preheat your oven to 375°F (190°C). Grease a medium-sized oval or rectangular baking dish with butter so the gratin won’t stick.
2. Make the Cream Mixture:
In a saucepan, gently warm the heavy cream, milk, garlic, fresh thyme, nutmeg, salt, and pepper over low heat. Keep it warm until fragrant, but do not let it boil. Then remove it from heat.
3. Layer the Vegetables:
Arrange a single layer of sliced root vegetables in the baking dish. You can alternate types or colors for a beautiful pattern.
4. Add Cream and Cheese:
Pour a bit of the warm cream mixture over the vegetable layer — just enough to coat the slices. Sprinkle a generous layer of grated Gruyère cheese on top.
5. Repeat Layers:
Continue layering vegetables, cream, and cheese until you use all your ingredients. Finish with a top layer of cheese.
6. Bake Covered:
Cover the dish loosely with aluminum foil. Bake in the oven for 45 minutes to let everything cook and soften.
7. Bake Uncovered and Brown:
Remove the foil and bake for another 15–20 minutes. This step lets the cheese on top turn golden brown and bubbly, and ensures vegetables are tender when poked with a fork.
8. Rest and Serve:
Let the gratin cool for about 10 minutes so the sauce can set. Sprinkle extra fresh thyme over the top before serving.
Enjoy this comforting cheesy root vegetable gratin warm, perfect with roasted meats or a fresh green salad!
Can I Use Frozen Vegetables in This Gratin?
It’s best to use fresh root vegetables for this recipe because frozen ones can release extra moisture, making the gratin watery. If you must use frozen, thaw and pat them dry thoroughly before slicing and layering.
How Should I Store Leftovers?
Store any leftovers in an airtight container in the fridge for up to 3 days. Reheat gently in the oven or microwave, adding a splash of cream or milk if the gratin seems dry.
Can I Make This Dish Ahead of Time?
Absolutely! Assemble the gratin completely, cover with foil, and refrigerate for up to 24 hours before baking. Add a few extra minutes to the baking time if cooking straight from the fridge.
What Can I Substitute for Gruyère Cheese?
Good substitutes include sharp cheddar, Swiss cheese, or a mix of Parmesan with mozzarella for a great melt and flavor combo.
