Straw potato and celeriac cake

Method

1 Coarsely grate the potatoes and celeriac
(you can do this with the coarse-grating
blade of a food processor) and toss them
together in a bowl. Heat a large non-stick
frying pan over a medium-low heat, add
the oil and a third of the butter and, once
melted, scatter the potato and celeriac
mixture over the base of the pan.

2 Press down with the back of a spoon,
season and dot with another third of the
butter. Cook for about 20 minutes until a
uniform deep gold, lifting the potato cake
every now and again to check its progress,
and rotating the frying pan by a quarter to
ensure it colours evenly.

3 Loosen the cake and press the mixture
down again, then place a baking tray on
top and invert the pan. Add the remaining
butter and once it has melted slip the
potato cake back in. Tidy the sides and fry
for another 10 minutes or until equally gold
on the underside, rotating the pan by a
quarter now and again.

To make a dressing for the salad whisk
together 1 teaspoon of cider vinegar,
½ teaspoon of Dijon mustard, just under
½ teaspoon of caster sugar, sea salt and
black pepper. Whisk in 1 tablespoon of
walnut or hazelnut oil and 1 tablespoon
of groundnut or vegetable oil. Toss the
watercress with the dressing. Serve this
in a pile with a wedge of the potato cake,
with the pear and blue cheese to the side.