Nigella’s Christmas Feast: Celeriac and anchovy gratin
I adore celeriac, and here it lends itself perfectly to the deep umami of anchovies, their fierce rasp mellowed by the blanketing cream. I often make this up ahead of time, and leave it in a cool part of the kitchen for a few hours before it goes into the oven. It can also be left, covered, in the fridge for up to two days, making sure you let it get to room temperature before roasting it. Keep some of the celeriac-cooking water, too, in case it needs topping up.
1.5 litres cold water, plus more as needed
2 tbsp lemon juice
2 tsp sea salt flakes (or 1 tsp fine sea salt)
4 fat cloves of garlic
15g butter, plus more for greasing dish
300ml double cream
8 anchovy fillets
a good grinding of pepper
- Put the cold water into a saucepan large enough to take all the celeriac comfortably. It doesn’t have to be huge; I fit mine into a pan that’s 22cm in diameter and 9cm deep. Add the lemon juice and salt the water. Very carefully cut the celeriac into quarters then peel. In a processor or with a mandoline or, indeed, with the knife you used to cut and peel the celeriac, slice very thinly. (If using the slicing disc in the processor, you will probably have to cut each quarter in half.) Add to the lemony water in the saucepan, topping up with a little fresh water if the celeriac isn’t just about covered.
- Peel the cloves of garlic and drop them into the pan too, then bring to the boil over high heat. I put a lid on to make it faster, but keep an ear open so that you don’t miss when it starts boiling. Cook on a rollicking boil, partially covered, for about 5 minutes until the pieces of celeriac are tender, but not so soft that they’re cooked through.
- With a large sieve over a batter jug or bowl, strain the celeriac; I do this because I keep the liquid for making stock. If you know you won’t, then lower in a ladle or measuring jug to remove some of the celeriac-cooking water – get about 250ml or a cup, just in case – to add to the anchovy cream later, and just drain the celeriac in a colander in the sink, though it pains me to write those words.
- Once the celeriac is cool enough to handle, remove 75g of it (I go for the little chips and pieces, so that I have as many of the proper slices as I can for layering up in the dish later) and put into a bowl you can use with a stick blender. Retrieve the garlic cloves and add those to your bowl, too.
- Butter your chosen dish (the one I use has internal measurements of 26cm x 18cm x 5.5cm) and fill with the celeriac slices.
- Add the cream and anchovy fillets to your bowl of celeriac offcuts and garlic, along with 100ml of the celeriac-cooking water, then give a generous grinding of pepper and blitz with a stick blender. Resist the temptation to knock this back in one – or is it only me? – and pour over the celeriac in its dish (adding more of the reserved water should the cream not just cover) and leave for a couple of hours – or up to two days in the fridge – or blithely proceed straightaway.
- Heat the oven to 190C/ 170C fan/gas 5. Dot the 15g of butter on top of the cream-covered celeriac and cook for 50 minutes to 1 hour, until piping hot and golden brown, with the odd scorched bit on top.