Herring goulash

Gut the herring, clean from the bones, drizzle with lemon juice and cut into cubes. Finely chop the onions, fry on a grind, add flour, mix, brown. Stirring add a little hot water, bringing to the consistency of a thick sauce, salt, add red pepper and cook 10 minutes. Add Wurster sauce and pieces of herring, bring to readiness over low heat. Just before serving, add the yogurt and a slice of lemon zest.