Celery Root Gratin

This rich and indulgent dish offers a twist on the classically prepared French favorite Potato Gratin. However, instead of using Potatoes they are replaced with another root vegetable. Celery Root (otherwise known as Celeriac) is a wonderful vegetable that offers very similar textural qualities to Potatoes, making it perfect to use as an alternative. In this recipe we show you how to make an amazing Celery Root Gratin, which is a layered dish of thinly sliced Celery Root combined with Cream and Cheese which is slowly baked until tender and delicious

Inspiration for this dish

In the Dinnertime Somewhere household we watch a lot of cooking TV. Perhaps like many of you, throwing on some cooking shows is a great way to enjoy some low effort TV while we’re winding down for the day. I’ve noticed over the last 6 months or so that Celery Root is popping up everywhere. From Top Chef to every show you can think of on the Food Network, everyone seems to be cooking with Celery Root!

I feel this is mainly due to Celery Root being a much more unique and perhaps interesting ingredient than Potatoes! Making a Potato Mash doesn’t sound too fancy on a cooking competition does it? But, making Celery Root Mash just sounds so much fancier!

What is the difference between Celery Root and Potato?

While their texture and appearance (once prepared) are quite similar, the flavor is very different. I would say Potatoes offer more of a neutral, slightly earthy flavor and really benefit from the ingredients they are cooked with. Celery Root on the other hand has a very strong Celery flavor. It’s an ingredient to be wary of when using, because you need to consider using ingredients to complement the Celery flavor, and not compete with it

The good news is that Celery Root pairs with so many ingredients. Celery is one of the main ingredients in mirepoix (being Carrots, Onion, and Celery) and it forms the base for millions of dishes. So you can pair loads of amazing ingredients with Celery Root and it’s going to taste great

For our Celery Root Gratin, the core ingredients other than the Celery Root are Cream, Shallots, Garlic, and Cheese. This combination of flavors is fantastic however you prepare them, but especially good (and indulgent) when baked into a cheesy, rich Gratin!

How to make Celery Root Gratin

This recipe is like our classic Potato Gratin recipe and produces that amazingly rich and creamy textured result. The only difference between the two recipes is the portions of liquid. I have found that Celery Root does not absorb as much liquid as Potatoes, so therefore does not need as much Cream as you would add to traditional Potatoes Gratin

To prepare the Celery Root, first slice away the outer skin to reveal the beautiful white flesh inside. We want to thinly slice the Celery Root into strips, so the best way to do this is with a mandoline. If you don’t have a mandoline that’s ok, you can use a sharp knife. Just take your time and be careful, as we want to cut the strips quite thin

A mandoline is the best option here as you can produce even strips of thin Celery Root. The more even the strips you can cut the better, as that will ensure an even cook

Soak the Celery Root in seasoned Heavy Cream for 30 minutes before assembly

To allow the Celery Root to begin to absorb the Cream, Place the thin slices into a large bowl and add your Heavy Cream. To the Cream we also want to add some Milk, Garlic (you can either use Powder or finely diced fresh Garlic), Thyme, Salt, Pepper, and Shallots

Add a generous amount of Salt and Pepper, as like Potatoes, Celery Root loves Salt and can take on quite a lot of it. The Salt will help to bring out the amazing flavor of the ingredient, so be generous. Give the Celery Root a good stir through so it’s covered in the Cream then allow it to sit for 30 minutes at room temperature

Once you reach the top, finish the assembly by adding a generous sprinkling of grated Parmesan Cheese and some dried Herbs

Assembling the Celery Root Gratin

We create a Gratin in a similar way you would a Lasagna, by layering the strips of Celery Root then adding Cheese in between each layer into a deep sided baking dish. You don’t need to be super precise about your layers of Celery Root, just ensure you’ve got full coverage on each layer

Once you’ve added a layer of Celery Root, add a small amount of your Cheese Mix (we used a combination of Cheddar and Parmesan). Don’t add too much, just a light sprinkle. You’ll probably get about 8 – 10 layers into a typical baking tray, so there will end up being quite a lot of cheese in there anyway

Also try to ensure that you get an even amount of the Garlic and Shallots from the Cream liquid into each layer. You’ll need to dig around with your hands to the bottom of the bowl to get those Garlicky, Oniony bits, but it’s well worth the mess

Once you’ve completed your layering, pour in a little bit of extra Cream (about ½ cup is enough) then finish with a more generous sprinkling of Parmesan Cheese and finish with some dried Herbs (we went for Oregano). Now your Celeriac Gratin is ready to be baked in the oven!

Cooking the Gratin

The cooking time is a lot longer than you think; I’ve found that this dish requires about 2 ½ – 3 hours of total baking time to ensure the Celery Root is cooked well and becomes nice and tender. This long cooking time is due to the overall density of the dish. We’ve loaded this thing up with a whole Celery Root and lots of Cream and Cheese, so it’s going to take some cooking

Cover the whole dish with foil and place it in the oven at 350F. Cook it for about 2 ½ hours and then check the doneness of the Celery Root by stabbing it with a sharp knife. If the is little to no resistance when stabbing it, it’s cooked. If there’s a lot of resistance to the knife, put it back in the oven for another 30 minutes then check again

For the last 10 – 15 minutes, remove the foil and switch the oven to broil. This will allow the top of the Gratin to caramelize and get a wonderful, charred color to it. When broiling anything I like to keep a close eye on it to ensure it doesn’t burn

The most important step when making Gratin

You may think at this point we’re all done and it’s time to dive in. Not so fast! Once the Gratin is cooked it’s going to be a billion degrees inside. What you need to do is remove it from the oven and allow it to sit at room temperature for about 20 minutes to cool

This step is critical, because it will allow the dish to settle and keep its shape as it cools. If you cut into a Gratin straight out of the oven you’re going to end up with a soupy, messy dish. Give it some time to cool so when you cut it out of the pan it will retain it’s beautiful shape

It’s tough because the temptation to dive in and eat it immediately is great! Especially given how amazing the dish smells. Just be patient however! Hey, you can use these 20 minutes to make some amazing Steak recipes that’ll go great with this Cheesy Celery Root Gratin dish

Celery Root Gratin Recipe

Ingredients

• 1 large Celery Root
• 400ml. Heavy Cream
• ½ cup Whole Milk
• 2 Shallots, finely diced
• 4 Garlic Cloves, finely diced (or 2 tsp. Garlic Powder)
• 2 tbsp. Thyme Leaves, stems removed
• ½ cup Cheddar Cheese, grated
• 1 cup Parmesan Cheese, grated
• 1 tsp. Dried Herbs (eg: Oregano or Parsley)
• Salt and Pepper
  
  

Equipment Needed: Mandoline Slicer

Instructions

1. Peel the skin from the Celery Root and then slice the flesh into thin slices using a Mandoline
2. Combine Heavy Cream, Whole Milk, Shallots, Garlic, Thyme 3 tsp. Salt, and 1 tsp. Black Pepper in a large bowl and mix well. Add the Celery Root Slices and coat / submerge. Leave at room temperature for 30 minutes
3. Add a layer of the Celery Root to large, high sided baking tray. You can slightly overlap the slices, just ensure you cover a full layer and ensure the layer has some of the Garlic and Shallots
4. Add a little bit of Cheddar and Parmesan (not too much) to the layer and then repeat the process until the pan is full
5. Finish by pouring in about ½ cup of the remaining Cream mixture along with all of the remaining Shallots and Garlic. Grate over a generous amount of Parmesan Cheese to cover the top of the Gratin and sprinkle with Dried Herbs
6. Cover with aluminum foil and bake in the oven pre-heated to 350F for 2 ½ hours. Once the Celery Root is completely cooked (little resistance when stabbed with a knife), remove the foil and set the oven to Broil
7. Broil the Gratin for 10 minutes, or until the top is golden brown and caramelized. Remove from oven and allow to cool for 20 minutes at room temperature before serving
   
   

Recipe Notes

• You can prepare the Celery Root by using a sharp knife instead of a Mandoline. Just ensure you cut even, thin slices. If slices are cut thicker the cooking time will increase
• Check the doneness of the Celery Root after 2 hours by stabbing it with a sharp knife. If there is still some resistance, continue baking, covered for 20 – 30 minutes and check again
  
  

This amazing Celery Root Gratin offers and fun and unique twist on the more classic Potatoes Gratin and it tastes great! It’s an indulgent side dish that’s perfect to enjoy with a nice piece of Protein, especially Steak. We highly recommend you give this delicious side dish a try

For more tasty Side Dishes, check out these amazing recipes:

• Rosemary and Parmesan Roast Potatoes
• Mexican Street Corn
• Broccolini with Oyster Sauce
• Japanese Pickled Radishes
  
  

Happy Cooking!