It is also an excellent complement to fish, game, or duck, and works well with lamb tagine or calf’s liver. It is brilliant because it’s so similar to mashed potatoes but more subtle. It’s comforting but also fresh and vibrant. I have to restrain myself from making it too often.
The quantity can easily be adapted, with proportions of about 60% – 40% celeriac to potatoes in favor of the celeriac (a lot of celeriac needs to be removed in the peeling process, so it’s always a good idea to buy a bit more than you think you need).
4 Tbsps Coarse sea salt
4 small heads celeriac (about the size of an orange)
3 medium Yukon Gold potatoes
2 large bunches flat-leaved parsley
Good olive oil
4 Tbsps good butter
Sea salt and freshly ground black pepper
Freshly grated nutmeg
Bring two large pots of water to a boil each with 2 Tbsps of coarse sea salt.
Peel the celeriac and the potatoes and cut them into large chunks, all about the same size so they take the same amount of time to cook.
Place each vegetable in a separate pot of boiling water and cook until soft. **The celeriac and potatoes must be cooked separately because they don’t take the same amount of time to cook through (the celeriac takes longer) and it’s important not to overcook the potatoes; if they start falling apart the consistency of the mash will be watery.** The cooking time depends on the size of the pieces of vegetable and how crowded they are in the boiling water, but I usually start checking the potatoes by poking them with a sharp knife after about 12 minutes, the celeriac after about 20 minutes. They are ready when the knife goes in with no resistance.
Meanwhile, wash the parsley and trim off the thickest part of the stems.
In a blender, purée the parsley with 4 tablespoons of olive oil and 2 tablespoons of water.
Once the roots are cooked, mash them with a potato masher or through a food mill (never in a food processor as the blade cutting through the potato starch makes the potatoes gummy). Mix in the butter, a good slosh of olive oil, and season with salt, pepper, and freshly grated nutmeg. Taste and adjust.
Reheat the mash over very low heat and at the very last minute just before serving add the parsley purée. Stir well until it is uniformly green. **The parsley must be added at the very last minute; if heated the parsley will turn brown and loose its vibrant flavor.**