The day before peel the onions, cut them in half lengthwise and cut them into fine strips. Wash the dill and shake dry. Pluck off little flags and cut roughly. Put the dill stalks aside.
Bring vinegar, 150 ml water, dill stems, onions, peppercorns and bay leaf to the boil. Simmer for about 1 minute, remove from heat and pour into a bowl. Remove dill stalks. Stir honey into the brew and dissolve.
Admit dill flags. Let the brew cool down.
Rinse matie cold, dab dry, cut into pieces. Add to the stock, fold in. Cover and leave in the fridge for at least 12 hours.
The next day wash the potatoes and cook them covered in salted water for about 20 minutes. Drain potatoes, rinse with cold water and peel. Melt butter. Lift the maties out of the stock, drain a little and serve with the boiled potatoes.
Drip liquid butter over the potatoes.