Rich and creamy Turnip au Gratin makes the best low carb potato substitute! Thinly sliced turnips are paired with a cheesy Alfredo-style sauce and baked to perfection.
Behold the lowly turnip. It’s not the most interesting or attractive of vegetables and most people ignore it altogether. But I would argue that they are missing out.
This Turnip au Gratin is absolutely worth a second look. Not only that, it’s worthy of making again and again. Because it takes the lowly turnip and turns it into something spectacular.
I use turnip frequently in recipes like Keto Beef Stew or Easy Keto Seafood Chowder, where it subs in nicely for potatoes. But in this creamy keto side dish, turnip is the star of the show.
Believe me when I say that this low carb root vegetable has never tasted so good!
Why you need to try this recipe
My mother made scalloped potatoes frequently when I was a kid. They were one of her go-to side dishes and they went with just about everything. This Turnip au Gratin takes me back to those days.
I had to test this recipe a few times to get it right, and I learned some great tips along the way. Turnips can be on the bitter side and take a long time to bake through properly. But smaller turnips are much less bitter and soften more during cooking.
I also borrowed a great trick I found in a recipe for scalloped potatoes. Sautéing the turnip slices in butter first makes them all them more luscious and tender.
The end result was a deliciously creamy and satisfying side dish with only 5.8g net carbs per serving. And it pairs perfectly with all of your main dishes. It’s so good with Air Fryer Pork Chops!
Ingredients you need
- Turnips: Make sure you choose turnips that are on the small side, no bigger than 3 inches in diameter. Smaller turnips have less bitterness and cook through more easily.
- Garlic: Fresh minced garlic adds the best flavor.
- Heavy cream: The sauce is similar to Alfredo and heavy cream is the best option for a thick consistency.
- Parmesan: Use freshly grated Parmesan for flavor and to add thickness to the sauce.
- Glucomannan: A little thickener like Glucomannan or xanthan gum will help keep the turnip au gratin from becoming watery as it cooks.
- Grated cheese: I used white cheddar but other hard cheeses would also work.
- Pantry staples: Butter, salt, pepper.
Step by Step Directions
1. Using a mandolin slicer, slice the turnips about ⅛ inch thick.
2. In a large saucepan, heat 1 tablespoon of the butter. Add half of the turnip slices and toss to coat in the butter. Cook 3 minutes, stirring frequently.
3. Arrange the turnips in an 8 or 9 inch ceramic baking dish in an overlapping pattern. Repeat with the remaining butter and remaining turnip slices.
4. Add the garlic to the pan and sauté in the butter until fragrant, about 30 seconds. Stir in the heavy cream and cook until it simmers, then stir in the Parmesan. Season to taste with salt and pepper and then whisk in glucomannan.
5. Pour the cream mixture over the turnips and cover the whole baking dish with foil. Bake 40 minutes. Remove the foil, sprinkle with cheese, and bake another 10 to 15 minutes, until turnips are tender.
6. Turn on the broiler and broil 1 to 3 minutes to brown up the top, if desired.
Make sure you cut the turnip in very thin, even slices so that they cook through evenly. This is easiest to do with a mandolin slicer. You can also try using the slicing blade of a food processor.
Large turnips tend to be much more bitter and tough than small ones. So it’s important to keep them on the small side. Most stores carry purple turnips, which tend to be larger. But as long as you choose the ones under 3 inches in diameter, you should be fine. If you can find the smaller white salad turnips, those work really well in this turnip au gratin.
After some research, I found that quickly sautéing the slices in butter had several advantages. It coats each individual slice in oil, which helps them not stick together during baking. It also kickstarts the cooking process, ensuring less bitterness and more tender au gratin.
Frequently Asked Questions
Turnips are a great choice for keto diets, as they have far fewer carbs than most root vegetables. A medium turnip weighs approximately 120 grams and has 8 grams of carbohydrate and 2.2 grams of fiber. They also have more Vitamin C and other antioxidants than potatoes.
If the turnips are large, the skin will be much tougher and you should consider peeling them. But smaller turnips have thinner skin and don’t need to be peeled prior to baking or cooking.
If your turnips are bitter, they are likely too big and a bit tough. You can still use them but you will want to skin them first. You can also boil them in some salted water for 10 minutes or so. This helps reduce the bitterness and soften them for cooking.
Store the gratin, tightly wrapped, in the fridge for up to 5 days. Then gently re-warm it in the oven or the microwave. You can also freeze turnip au gratin for several months. Let it thaw completely before re-warming.
Serve this Turnip au Gratin with:
- Keto Pork Tenderloin
- Spinach Stuffed Chicken
- Easy Baked Halibut
- Walnut Crusted Chicken
- Standing Rib Roast
- Pecan Crusted Salmon
Turnip au Gratin Recipe
- 2 lb small turnips
- 2 tablespoon butter divided
- Salt and pepper to taste
- 2 cloves garlic minced
- ¾ cup heavy whipping cream
- 2 ounces grated Parmesan
- ½ teaspoon glucomannan or ¼ teaspoon xanthan gum
- 3 ounces grated Cheddar cheese
- Preheat the oven to 375ºF. Using a mandolin slicer, slice the turnips about ⅛ inch thick.
- In a large saucepan, heat 1 tablespoon of the butter. Add half of the turnip slices and toss to coat in the butter. Cook 3 minutes, stirring frequently and making sure to separate the individual slices.
- Arrange the turnips in an 8 or 9 inch ceramic baking dish in an overlapping pattern and season with salt and pepper. Repeat with the remaining butter and remaining turnip slices.
- Add the garlic to the pan and sauté in the butter until fragrant, about 30 seconds. Stir in the heavy cream and cook until it simmers, then stir in the Parmesan. Season to taste with salt and pepper and then whisk in glucomannan.
- Pour the cream mixture over the turnips and cover the whole baking dish with foil. Bake 35 minutes. Remove the foil, sprinkle with cheese, and bake another 10 to 15 minutes, until the turnips are tender.
- Turn on the broiler and broil 1 to 3 minutes to brown up the top, if desired.
This is sooooo delicious!!!! I did tweak the method a bit: I used rutabaga (cut large rectangular chunks then sliced them to size) instead of turnip. I pre-cooked the slices for about 8 min in the microwave (fork tender) then seasoned them in the casserole dish with butter, salt and pepper, topped with the Parmesan sauce and grated cheddar, and skipped the foil bake. Took about 20-25 min to come to a bubbling, beginning-to-brown perfection. The sauce is SPECTACULAR!!! And the leftovers were super-tasty, too!
Wow, I made this today ahead of time for Easter tomorrow. Of course I had to try it before tomorrow and it is delicious. You almost wouldn’t even know it wasn’t potatoes!
Betsy Mickey says
This recipe came in just in time to use the salad turnips I had picked up at the Farmer’s Market, so I gave it a try last night. It was delicious, and no keto apologies were necessary! I also found the leaf stems at the top to be the perfect handle to hang onto while safely slicing the turnips on the mandoline. This will become a staple recipe in my house.
Fantastic! Salad turnips are the best… but they aren’t always easy to find.
Valerie Ingersoll says
I made this. It was so good. So much flavor and so easy to make.
Will rutabagas work in place of turnips?
I have never had either before, but someone gave me a bunch of rutabagas & I don’t know what to do with them.
Tried these for lunch today and wow! They turned out perfectly. Looking forward to leftovers. I happened to have a tablespoon or so of diced onion so I threw that in too. These will be on the table again.
Yay!!! Glad you enjoyed!
I have all of the ingredients, sans glucomannan or xanthan gum. I cannot stand the slime they produce.
As an alternative, would an egg yolk work? I often use them in lieu of the two mentioned above for thickening gravy, etc. I have a small brisket in the slow cooker and thought this would be a great side dish.
You’re certainly welcome to try it.
I tried it. I just pulled it out of the oven. We’ll see what happens! (Crossing fingers) I have to say, it smells amazing! ‘m in the UK, and it’s dinner time.
Thank you for another great recipe!
How did the egg yolk work?