The "Silver Darlings" Sorry - you can't make these until the season starts
in Late August/early September - unless you got a private source!
If you have a source for frozen herring fillets, you can use them, I have
and very successfully.
This dish is Cheap as Chips, lots of Omegas and not a carb in sight.

6 to 8 Herring Fillets.
1 small onion, chopped.
2 Bay Leaves.
12 Black Peppercorns, lightly crushed (Mignonette Pepper)
Ground White Pepper.
1/4 Teaspoon Salt.
1/4 Cup Water - filled to a full cup with Ordinary Vinegar - can be an
acetic acid solution or distilled malt vinegar, but NOTHING else.

Lay the fillets down skin side up on a piece of Clingfilm.
Crush the backbones until they crack, the length of the fish.
Trim off the obvious fins with scissors.
Turn the fillets over and remove the Backbone with the aid of a small
knife - it should come away easily.
Remove any more obvious pin bones with a pair of tweezers.
Season the flesh side of the fillets lightly with White Pepper and Salt.
Roll each fillet up from tail to head, and place in a saucepan that's JUST
broad enough to hold them. (Any larger and the fillets may unfold during
cooking)
(Some people use wooden skewers to secure them, but traditionally, NOT used)
Drop the Bay Leaves and Onions on top of the Fillets and then add the
peppercorns.
Top up with the Vinegar solution. Put on a lid and open the Kitchen Window
and close the door to the rest of the house. (IMPORTANT!)
Bring up slowly to a rolling boil.
Turn down to a simmer and let that happen for 2 minutes.
Turn OFF the heat and leave for 2 hours until cold.
Transfer the fishes to a clean dish and strain the cooking liquors through a
seive over the fishes.
Cover and leave in the fridge for at least 6 hours before just transferring
the fish (minus Liquor) to a plate of Salads.

SOME of the fish oils become unavailable in this recipe, because of the
pickle/chill/straining process.

NOTE: Some people use more or less concentrate of vinegar. (I use ALL
vinegar and it's what MY people prefer)
Some people add chillies to the pickle, but be warned - you
need to use quite a lot for there to be any effect. Try the original first.