Make sure the ingredients are at room temperature. Mix the egg yolk with the salt, the pepper, half a teaspoon of quince vinegar and 1 teaspoon of pumpkin seed mustard. Use an electric hand mixer.
With the hand mixer, mix in the pumpkin seed oil, first only in drips and then gradually increasing the volume until it becomes a thick pulp.
The mayonnaise thus prepared should be consumed on the same day. Raw egg yolk can be replaced with the grated yolk of a boiled egg, and then be stored in the fridge for several days for consumption.
Boil the potatoes whole and unpeeled. Pour off the water, and peel them while they are still hot. Cut them into rings, and then place them in a bowl. Add salt and pepper.
Mix the hot water and 1 tablespoon of quince vinegar, and pour it on the potatoes. Stir it slowly until the potatoes absorb the liquid. Finally, mix in carefully the pumpkin seed mayonnaise until it reaches a creamy consistency.
Serve it with finely chopped chives.