Herring Under a Fur Coat

Taste a corner of a herring fillet before anything else.

Soak the fillets in cold water for an hour if it is fiercely salty, and use them as they come if it is not. Everything else in this dish is bland, so the herring sets the seasoning for all of it and there is no correcting it later.

Run your fingertips down each fillet, feeling for pin bones, and pull out any you find with tweezers.

Cut the fillets into 1cm pieces and pat them dry.

Cook the beetroot whole and unpeeled in its own pan of simmering water for 45-60 minutes, until a skewer goes to the centre with no resistance.

Cook the potatoes and carrots whole and unpeeled in a second pan with the 10g of fine salt for 20-25 minutes, lifting each out as it gives to a skewer.

Boil the eggs for 9 minutes from the moment the water returns to the boil, then cool them under cold running water and peel them.

Cool everything completely before a single layer is built. Warm vegetables slump, and mayonnaise spread on anything warm thins and slides straight out of the stack.

Peel the cold beetroot, potatoes and carrots.

Grate the potato, carrot, beetroot and egg on the coarse side of a box grater, each into its own bowl, and wash the grater between the beetroot and everything else.

Rinse the diced onion in a sieve under cold water, squeeze it dry and turn the cider vinegar through it.

Leave the onion in the vinegar for 10 minutes, which takes the raw heat off it and gives the one sharp note in an otherwise rich dish.

Spread the herring pieces over the base of a straight-sided glass dish about 20cm across, in a single even layer.

Scatter the vinegared onion over the herring.

Spread the grated potato over next and press it flat with the back of a spoon.

Spread a third of the mayonnaise over the potato in a thin layer, right out to the edges of the dish.

Spread it thin and take it to the edge every time. The mayonnaise is mortar between layers rather than a filling, and a thick soft layer lets the stack slide apart the moment a knife goes into it.

Add the grated carrot, press it flat and spread another third of the mayonnaise over it.

Add the grated egg and press it flat.

Squeeze the grated beetroot hard in your hands over the sink before it goes on.

Get that juice out. Beetroot holds a great deal of water, and a wet top layer weeps pink down through every layer below it overnight and leaves the whole dish sodden.

Spread the squeezed beetroot over the top and level it.

Spread the last of the mayonnaise over the beetroot and smooth it flat with a palette knife.

Cover the dish and refrigerate for at least 8 hours, and overnight if you can.

Give it the full night. This is the step that turns six loose layers into something that holds its shape on a plate, and it is also how the salt of the herring travels through the rest of it.

Scatter the dill over and grind the peppercorns over the top just before serving.

Cut down through every layer to the base of the dish and lift each slice out with a palette knife.

Keep it covered in the fridge and eat it within two days.