Kosher salt
Canola, vegetable, or other neutral oil
To make the watercress puree, melt the butter in a pan along with
the bay leaf and when the butter’s thoroughly melted, add the
leeks. Cook them gently on medium-low heat for 5 minutes or so.
When the leeks are nice and soft, add the cream and season with
salt. Bring the cream to a boil and remove the bay leaf*. Add the
watercress and stir to coat. If it’s not coated, add more cream
while the pan is still on the boil.
When the watercress has wilted slightly after just a minute or
two, add the watercress and most of the liquid to a blender.
Carefully blend (cover the hole in the lid with a towel) and adjust
the consistency: it should be almost soupy. If it’s not, add more of
the remaining liquid. Add the lemon juice, blend one more time,
then taste for seasoning. Set aside.
For the mandarin salad, simply toss all the ingredients together
in a large bowl, adjust for salt, and set aside.
Finally, run your finger along the length of the trout to check
for bones. If you find bones, use pliers or your fingers to remove
them carefully.
Season the fish on both sides with salt. Heat 2 cast-iron
skillets* on high heat until very hot. Add a splash of oil and then 2
trout fillets per pan, skin side down, and press the fish into the
pan with your hands or a spatula.
Cook until the trout is almost completely opaque and the skin