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How It Works
Golden turnip au gratin with thyme in a baking dish, with a creamy layered serving lifted on a spoon.
Sides Vegetarian Fall Winter Gluten-Free Nut-Free

Turnip Au Gratin Recipe

Tender sliced turnips baked in a creamy garlic and thyme sauce under a golden layer of melted cheddar.

Prep 20 min
Cook 1 hr
Total 1 hr 30 min
Servings 6 servings
Difficulty Easy
Jump to Recipe Adapt This Recipe
Oven375°F · conventional Air fryerConversion not recommended

Contains: Milk

The base recipe contains milk. If adapting for a milk allergy, use products clearly labelled dairy-free and check packaged dairy-free cheese alternatives for any other allergens.

WHY IT WORKS

Why This Recipe Works

01

Thin Slices Cook Evenly

Slicing the turnips about 1/8 inch thick helps the layers soften at the same rate and gives the gratin a tender, cohesive texture.

02

Creamy Without Flour

Heavy cream and whole milk make a rich sauce without a flour-based thickener, keeping the turnip flavor clear and the recipe naturally gluten-free.

03

Finish Uncovered

Baking covered first softens the turnips, then uncovering the dish with reserved cheese creates the golden, lightly crisp gratin topping.

WHAT YOU’LL NEED

Equipment

2-quart baking dish
Mandoline or sharp knife
Medium saucepan
Whisk
Aluminum foil

THE RECIPE

Ingredients & Method

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Method

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  1. Heat the oven to 375°F. Rub the softened butter over the base and sides of a 2-quart baking dish.
  2. Slice the peeled turnips into even rounds about 1/8 inch thick using a mandoline or sharp knife.
  3. In a medium saucepan, combine the heavy cream, whole milk, garlic, 2 teaspoons (tsp) of the thyme, salt, black pepper and nutmeg. Warm over medium-low heat for 4 to 5 minutes, until steaming but not boiling, then remove from the heat.
  4. Set aside 1/2 US cup of the cheddar. Arrange one-third of the turnips in the baking dish and sprinkle with one-third of the remaining cheese. Repeat twice to make three layers. Pour the warm cream mixture evenly over the turnips and press the layers down gently.
  5. Cover the dish tightly with aluminum foil and bake for 35 minutes.
  6. Remove the foil. Sprinkle the reserved cheddar and remaining 1 teaspoon (tsp) thyme over the top. Bake uncovered for another 20 to 25 minutes, until a thin knife slides easily through the center and the top is bubbling and golden brown.
  7. Let the gratin rest for 10 minutes before serving.

COOKING GUIDANCE

Practical Cooking Notes

Doneness

The gratin is ready when a thin knife slides easily through the center layers and the top is bubbling and golden brown.

Make Ahead

Assemble the gratin, cover it and refrigerate for up to 12 hours before baking. Bake it directly from the refrigerator, allowing about 5 to 10 extra minutes during the covered stage if needed.

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Dietary options

Make This Recipe Work for You

Only straightforward swaps are offered automatically. If changing a defining ingredient would effectively create a different dish, that conversion is left out.

Already Vegetarian ✓ Already Gluten-Free ✓
Make It Vegan

Change the following ingredients:

Replace1 tablespoon (tbsp) unsalted butter, softened

With1 tablespoon (tbsp) vegan butter, softened

Replace1 1/4 US cups heavy cream

With1 1/4 US cups unsweetened plant-based cooking cream

Replace3/4 US cup whole milk

With3/4 US cup unsweetened soy milk

Replace1 1/2 US cups shredded sharp cheddar cheese, made with vegetarian rennet

With1 1/2 US cups shredded dairy-free cheddar-style cheese

Use plant-based butter, cooking cream, milk and a good melting dairy-free cheddar-style cheese. The finished sauce may be slightly less rich depending on the products used.

Make It Dairy-Free

Change the following ingredients:

Replace1 tablespoon (tbsp) unsalted butter, softened

With1 tablespoon (tbsp) dairy-free butter, softened

Replace1 1/4 US cups heavy cream

With1 1/4 US cups unsweetened dairy-free cooking cream

Replace3/4 US cup whole milk

With3/4 US cup unsweetened dairy-free milk

Replace1 1/2 US cups shredded sharp cheddar cheese, made with vegetarian rennet

With1 1/2 US cups shredded dairy-free cheddar-style cheese

Replace the four dairy ingredients with like-for-like dairy-free versions that are suitable for baking and melting.

For allergies, intolerances or strict dietary requirements, check the labels of the specific products you use. These swaps do not certify a recipe or ingredient as allergen-free.

Recipe Notes

Ingredient Notes

Choose firm, smooth turnips that feel heavy for their size. Small to medium turnips tend to be milder and less woody than very large ones. A mandoline makes it easier to keep the slices evenly thin. The cheddar is specified with vegetarian rennet so the finished recipe is suitable for vegetarians.

Useful Substitutions

A vegetarian Swiss-style or Gruyere-style cheese can replace the cheddar for a nuttier flavor. Half-and-half can replace the heavy cream and milk mixture for convenience, although the finished sauce may be slightly lighter.

INGREDIENT QUALITY

Quality Note

For the most even texture, keep the turnip slices close to 1/8 inch thick from the first layer to the last. A mandoline is helpful, but use its hand guard and follow the manufacturer's safety instructions.

SPEND LESS

Cost-Saving Tip

Whole turnips are usually better value than prepared sliced vegetables, and grating cheese from a block can cost less than buying the same amount pre-shredded.

COOKING TIPS

Tips

Slice the Turnips Evenly

Aim for slices about 1/8 inch thick. Uneven slices can leave some pieces firm while thinner ones become very soft.

Do Not Boil the Cream

Warm the cream mixture only until steaming. Boiling can make the dairy more likely to separate during baking.

Keep It Covered First

The covered baking stage traps steam so the turnips soften before the cheese topping is browned.

Rest Before Serving

Let the gratin stand for 10 minutes after baking so the creamy sauce settles and each serving holds together more neatly.

MAKE IT LAST

Storing, Freezing & Reheating

Storing

Cool leftovers promptly, cover and refrigerate for up to 4 days.

Reheat in the Oven

Cover the gratin and warm at 325°F until hot through, then uncover for the last few minutes if you want to refresh the browned top.

Reheat in the Microwave

Microwave individual portions in short intervals until hot throughout. The topping will be softer than when reheated in the oven.

ESTIMATED PER SERVING

Nutrition

1 of 6 servings

375 kcal Calories
30 g Fat 38% DV
19 g Saturated fat 95% DV
16 g Carbohydrate 6% DV
3 g Fiber 11% DV
9 g Sugars
11 g Protein
630 mg Sodium 27% DV
105 mg Cholesterol 35% DV

Nutrition information is an estimate. Where shown, % Daily Value uses standard US Daily Values for adults and children aged 4+; actual values vary with ingredient brands, exact quantities and portion size.

QUESTIONS

Turnip Au Gratin FAQs

Do I need to cook the turnips before making the gratin?

No. Thinly sliced turnips cook directly in the cream mixture. The covered first stage of baking provides enough steam to soften them.

How thin should I slice turnips for au gratin?

About 1/8 inch thick is ideal. A mandoline is the easiest way to make consistently thin slices, but a sharp knife also works.

How can I make turnip au gratin less bitter?

Choose smaller, fresh turnips, peel them well and avoid very large or woody roots. Cream, milk and cheese also balance the natural peppery edge of turnips.

Can I make turnip au gratin ahead of time?

Yes. Assemble the gratin, cover and refrigerate it for up to 12 hours before baking. A chilled dish may need about 5 to 10 extra minutes during the covered baking stage.

Why is my turnip gratin watery?

Turnips naturally release moisture as they cook. Slice them evenly, use the stated dairy quantities and let the finished gratin rest for 10 minutes so the sauce can settle before serving.

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