I just asked my father 'bout the details, here they are:
-cooked potatos, sliced, have to be still hot/warm, so they soak up the vinaigrette
-vinaigrette (two parts oil, one part whitewine vinegar, salt, pepper, garlic)
-onions
-chives
mix all these ingredients then:
-some some grinded nutmeg and
-a cup of hot broth (made of a stock cube)
on top, then mix again, voilą...
I'll try this without blowin up my kitchen and shall report back!