Anyone who knows my cooking will know that I make quite a lot of gratins. I love the idea for adding a hidden layer for vegetables, be it leeks and mushrooms, chard, kale, cavalo nero or some other leafy greens or cabbage and bacon. I like to use a variety of different root vegetables too and I have experimented with mushroom and leek, beetroot, parsnip, sweet potato, jerusalem artichoke and kohl rabi to name but a few. But this Potato and Fennel Gratin was a new idea and although it sounds plain, it is one of those dishes which somehow manages to taste more than the sum of its parts. It is somehow deeply satisfying and I implore you to give it a go.
Fennel, Potato and Parmesan Gratin
750g potatoes, peeled
500g trimmed fennel
750mls double cream
3 garlic cloves
Small bunch of thyme
Pinch chilli flakes
50g freshly grated parmesan
Sea salt and freshly ground black pepper
Put the cream, milk, garlic cloves, a pinch of chilli flakes and the bunch of thyme in a heavy bottomed saucepan and infuse over a low heat for as long as you have got. Check that it does not boil over, or catch as it reduces. Preheat the oven to 170C. Meanwhile thinly slice the potatoes and the fennel. A mandolin or a food processor is good for this. In a large gratin dish, put a layer of half of the potato, top with the fennel and then finish with the rest of the potato slices. Season the cream well with salt and pepper. Remember it has to season all the potatoes and fennel as well so it should be quite salty. Pour the cream mixture through a sieve over the potatoes. Scrape the sieve to make sure that you squeeze though all the garlic and the juices from the thyme. Press down the potato so that the cream mixture comes up to the top of the top layer of potato. If not, top up with a little milk. Scatter over the parmesan. Cover with tin foil and cook slowly in the oven for about 1 – 1 ½ hours until a blunt knife inserts easily all the way through. Remove the tin foil and allow the parmesan to brown to your liking. Allow to sit for 10 minutes before serving.