Start by toasting the fennel, coriander
and mustard seeds in a dry frying pan
on a low heat, about 8-10 mins. Once
you start to smell the rich aromas of
the spices, you know they have cooked
through. If they start to smoke, the spices
will taste bitter and it would be better to
start again. Once toasted, roughly crush
using a pestle and mortar, or wrap the
spices in a tea towel and crush with the
base of a small saucepan. Stir in a pinch
of black pepper.
Scrape the skin sides of the salmon
with a knife to get rid of any remaining
scales, and scrape off as much of the
film of moisture you sometimes get (this
helps to get the skin crisp). Slash the skin
3 times, about 3cm in length, to stop it
shrinking during cooking.
Tip the spice mix onto a plate, lay the
fish on it, skin-side up, so that the spices
cover the underside of the fish. You can
do this a few hrs ahead to help infuse the
fish with the spices. You can also start
the sauce ahead – put the finely chopped
shallots in a pan with the vinegar, fish
stock and saffron. Bring to the boil, then
reduce by two-thirds. Set aside.
Put the potatoes in a pan and cover
with salted water. Bring to the boil and
boil for 1-2 mins only, then drain. Heat the
oil in a large frying pan, then add the
turmeric and chilli powder, if using. Toss
the potatoes in the spiced oil, then cook
for 5 mins without stirring. Shake the pan
and cook for 5-10 mins more, or until the
potatoes are cooked through. Season
and keep warm.
When ready to cook the salmon, rub
the skin sides with some oil, then fry in a
pan (skin-sides down) on a medium heat
with a little bit more oil, pressing down
lightly on the fish for a few secs when it
first goes in the pan. Don’t touch the fish
or move the pan for about 5-6 mins –
this ensures you get beautiful crisp skin.
When the edges start to look golden, turn
the fish over and cook for 1 more min.
While the fish is cooking, cook the
spinach in a large pan of boiling water
for 2 mins. Drain, then squeeze out the
excess water. Return to the pan and stir
in the butter. This will form a simple
emulsion, which will prevent water
running out over the plate. Season.
To finish the sauce, warm the pan of
reduced mixture until hot. Take off the
heat, then whisk in all the butter, reserving
2-3 cubes. Once the butter is
amalgamated, stir in remaining cubes.
Season with pepper and use immediately.
Place a spoonful of spinach in the
middle of each plate, then lay the salmon
on top. Scatter some potatoes and pour
some sauce around the fish. Sprinkle a
few sea salt flakes over the fish and serve.