Wash herrings and place in cold water for at least three hours (preferably overnight). Remove bones and skin from herrings and cut into small pieces. Wash potatoes and beetroot and cook separately for 20 minutes in boiling water.
Then rinse with cold water, peel and cut both into cubes. Dice cucumbers and ham. Wash apples, quarter them, cut out the core. Cut apples into pieces. Mix the prepared ingredients.
For the marinade, peel and chop the onions. Melt the fat, fry the onions in it until translucent and sweat the flour. Add beer, vinegar and mustard while stirring. Season with salt and sugar. Let it boil down a little and add it to the salad.
Wash the dill and chop it except for a flag for garnishing. Sprinkle over the salad. Serve garnished with lemon wedges and dill flags.