Classic Japanese Potato Salad · Kasahara

Peel the potatoes, rinse them briefly under water and cut them into bite-size pieces.

Cut the carrot into roughly 4 chunks and leave the skin on.

💡 Skin on and cut big, and it will be cut small later — this is not laziness. A carrot boiled in small pieces waterlogs and turns to sweet mush. Boiled in big pieces with its jacket on, it stays firm, then you slice it neatly afterwards.

Put about 2 pinches of salt in a pot, add the potatoes and carrot, cover with cold water and bring it up from cold. Boil until both are soft.

💡 From COLD water, not dropped into boiling. A potato thrown into a rolling boil cooks its outside to mush while the middle is still raw. Rising with the water, it heats evenly all the way through.

Meanwhile: slice the onion thinly, rub it with salt until it goes slippery and weeps, then rinse it under water and squeeze it really dry.

💡 Salt-rubbing draws out both water and the raw onion's harsh bite. Skip it and raw onion will dominate every mouthful — and the water it leaks later will thin your mayonnaise into a puddle.

Roll the cucumber on the board with salt (shiozuri), slice it into thin rounds, rub those with salt too, then rinse and squeeze them dry as well.

💡 Cucumber is about 95% water. Squeezed properly it turns from a wet passenger into something with a real snap — and it stops your salad going soupy in the fridge.

Hard-boil the egg and set it aside to cool.

When the vegetables are soft, lift the carrot out of the pot and tip away all the boiling water.

Put the drained potatoes back over LOW heat in the dry, empty pot and dry-roast them, shaking now and then, until the surface steam has gone and they look chalky and matte rather than wet.

💡 This is the step that separates his potato salad from yours. A boiled potato is soaked in water you cannot see. Leave it there and the mayonnaise never sticks — it slides around a wet surface and the salad tastes dilute and weeps in the bowl. Thirty seconds of dry heat drives that water off as steam and opens the starch up to take on flavour.

Turn the heat off and, while the potatoes are still hot, sprinkle over the salt, the sugar and the vinegar — a little at a time, not all in one go.

💡 Hot potato absorbs; cold potato repels. This is the same principle as seasoning boiled potatoes for any dish, and it is why his salad tastes seasoned all the way through instead of just coated. The vinegar is the surprise — you will not taste it as sourness, only as a brightness that stops 3 tbsp of mayonnaise feeling heavy.

Move the potatoes to a bowl, add the mayonnaise, usukuchi soy sauce, sugar and karashi, and mix with a wooden spatula, breaking the potatoes up as you go.

💡 The half-teaspoon of usukuchi soy and the dab of karashi are what make this Japanese rather than deli potato salad — a quiet savoury depth and a mustard warmth you notice only if they are missing.

Crumble the boiled egg in with your fingers, and add the carrot — now cut into 5 mm slices — along with the squeezed onion and cucumber.

Mix briefly and lightly — Kasahara's word is 'sakutto', a quick cut-and-fold, not a stir. Taste, and adjust with a pinch of salt if it needs it.

💡 Stop early. Every extra turn mashes more potato and beats air out of the mayonnaise; keep going and you have made a smooth paste instead of a salad with pieces in it. Lumps are the texture, not a mistake.

Pile it into a bowl and grind black pepper over the top.