For the tarte flambée, cut Bismarck herring and bell bell pepper into strips. Cut the spring onion into rings. Spread sour cream on the tarte flambée dough, spread herring, onion, green onion and bell bell pepper on top, season with salt and bell pepper.
Place in the preheated oven and bake at 250 °C for about 10-15 minutes until the edges are nicely browned.