hoisin -> caramalized Sauerkraut
Grandma did:
pan with some lard, then sauerkraut with bit sugar, fine cut sour apples and onions, some apple wine and caraway
All boiled till wine is thickened and Sauerkraut getting brown
Was added to roasted meat, potatoe dumpling, Himmel und Erde, ...
It shares with hoisin the fermented, sweet sour taste. but isn't a sauce. Luckily we barbarians eat it this way, There are restaurants which add cream and use a immersion blender to turn it into a sauce,
I like the classical way where you see the original parts and have less fat because of no cream.