Step 1

In a large bowl, mix the mayonnaise, mustard and lemon juice together thoroughly with a generous sprinkling of salt and some freshly ground black pepper, so it all becomes one sauce.

Step 2

Peel and quarter the celeriac, then, working quickly, coarsely grate it and stir into the sauce until evenly coated. Serve the celeriac remoulade with lots of toast and some dressed watercress. It will keep in the fridge for up to 2 days.