Celeriac and Potato Gratin with Cobnut Gremolata
How good does cooked cream taste? My mouth is watering just writing about it, but the moment of weakness over the lips and the lifetime of regret over the hips is a shocking thought within itself!
I think that potato gratin cooked in cream is a classic dish but has a split personality, it,bizarrely, is incredibly sophisticated but comforting at the same time, almost bordering on rustic home cooking.
I like a gratin which is moist and not too dry and for that reason I add a little bit of stock. The stock will prevent the cream from setting too much. For me a classic gratin has wafer thin slices of well seasoned potato embraced with a velvety and sumptuous cream, gently infused with garlic.
I did break the mould slightly and used a mixture of celeriac and potato for this recipe. I love the nutty earthy flavour of celeriac and the potatoes best suited for this dish are Desiree or King Edwards. You are looking for a fairly neutral potato with equal quantities of waxiness and flouriness. If the potato is too floury it will disintegrate and lose it’s structure as a layered gratin and if it’s too waxy then the potato layers will not stick together and just simply slide away from each other.
The addition of sauteed shallots and thyme adds a bit of natural sweetness to this sumptuous dish which is finished off with the delicious cobnut gremolata. All the flavours work brilliantly together, the lemon zest cuts through the richness and the crunch from the cobnut balances the softness of the celeriac and potato. A well balanced dish!
Mother Nature is looking after us again by providing cobnuts in the autumn for our dinner table. Cobnuts stem from the hazelnut family, however unlike the hazelnuts we intend to eat them fresh and do not generally store them throughout the year. There are many different varieties but Cobnuts fall into two main categories ,either green or golden. The cobnuts that I used in this recipe are the golden type and are the slightly older nut. Peeling the nuts was quite amusing because they were being eaten as fast as they were being peeled. The creamy nutty crunchy divine taste of the fresh cobnuts is amazing hence the perfect combination of cobnut with this creamy and sumptuous celeriac gratin.
Making this gratin a day in advance improves the flavour and for that reason it’s the perfect party dish. Make the gremolata on the day, just before serving ,as the lemon zest and thyme are best enjoyed once prepared. I have baked this recipe in a 2lb loaf tin lined with parchment paper and for that reason it cooks for 2 hours. However you can make it in any shape your heart desires but please adjust the cooking times accordingly. I have indicated in the recipe below how to test if the gratin is cooked. I think it would also make lovely and gorgeous smaller individual portions.
I served this gratin with a slow cooked shoulder of lamb, it would also be delicious served with beef, venison, pigeon, partridge, guinea fowl, chicken and duck. Personally I would not serve this gratin with fish as it’s very rich and needs something fairly robust in flavour to give your meal a good balance.
I realised how valuable my tricks and top tips have become to my readers and for that reason I could not ignore this one today. I’m known as being a bit of a perfectionist and in the past lining the tray with perfectly straight parchment paper was the order of the day . I would spend a long time removing all the creases, cutting little slits in the paper to line it perfectly and smooth. One day when I was baking a cake and asked the other half to line the tray I nearly had a heart attack when he grabbed the paper and crumpled it into a ball. I was nearly in tears and on my knees, screaming angrily “what on earth are you doing!?” He replied calmly that he was lining the tin, well I have put my perfectionism to the side and adopted his method as it surely works well and saves time, perfect! Crumple the paper, then open it up and it will fit easily into the tray, have a close look at the photo’s.
Celeriac and Potato Gratin
- 1 head of celeriac, approximately 350g raw prepared weight
- 3 medium Desiree potatoes, approximately 350g raw prepared weight
- 1 clove of garlic, crushed with the back of your hand
- 2 banana shallots
- 500ml double cream
- 100ml vegetable stock
- Salt and Freshly ground black pepper
- Sprig of thyme+ 1tsp finely chopped
- One bay leaf
- 30g butter
Preheat the oven to 150°C and grease a oven dish. I have used a 2lb loaf tin and lined it with parchment paper, however you can use a shallower and wider dish, please remember to adjust the cooking time accordingly, the cooking times for this recipe is for making the gratin in a loaf tin.
Pour the cream, stock, bay leaf, garlic, sprig of thyme and seasoning into a medium saucepan. Bring tot he boil and simmer for 5 minutes. Turn the heat off and leave the cream to infuse for 20 minutes.
Peel the shallots and slice into rings. Heat a non-stick frying pan with the butter and sauté the shallots until golden, add seasoning and the chopped thyme.
Peel the celeriac and potatoes, cut the celeriac into quarters. Using a sharp mandolin slice the celeriac and potatoes 2mm thick.
Season the sliced celeriac and potato generously with salt and freshly cracked black pepper
Bring the cream back to the boil and the infused cream through a fine sieve directly over the sliced potatoes and celeriac.
Start layering your gratin, first pour on a bit of cream, then layer the celeriac, then a thin layer of the sautéed shallots, then potatoes then cream and continue until all the ingredients are used. At this stageI give it a good press with my hands.
Let the gratin sit for 30 minutes before cooking.
Bake the gratin for 2 hours, as I said this is for a deep gratin in a loaf tin. If you make a flatter version then the cooking time should be at least 30 - 40 minutes less. Test if the potatoes and celeriac are cooked by inserting a metal skewer, if it glides in and out with ease it's cooked, if it feels a bit crunchy return to the oven and cook longer. Do not be tempted to turn the heat up before the gratin is cooked, as a high heat will curdle the cream and your potatoes will be raw, not good!
Let the gratin rest and before you are ready to serve place the gratin in a preheated oven at 200°C for 20 - 25 minutes to heat through and brown.
- 2tbs chopped fresh thyme
- Zest of one lemon
- 5 cobnuts
Remove the husks from the cobnuts, crack the shell and remove the nut. Use a coarse grater to grate the cobnuts.
Add the zest of the lemon and the chopped fresh thyme leaves.
Scatter the cobnut gremolata over the cooked gratin and serve.
Serves 8 - 10
Food Fanatics Tips
Please remember to adjust the cooking times if you are making this gratin in a shallower dish. It's a perfect party piece and the flavour is improved if its made a day in advance, remember to ensure that the gratin is hot all the way through when serving. Make the gremolata fesh just before serving.