Preheat oven (electric cooker: 225 °C/ circulating air: 200 °C/ gas: level 4). Meanwhile clean, wash and cut leek into rings. Cut liver loaf into strips. Heat the oil in a pan and steam the leeks for about 4 minutes, turning them over.
Season with salt and pepper, add Leberkäse and fold in. Mix sour cream and mustard. Remove the tarte flambée dough from the packaging and roll it out directly on a baking tray with the baking paper. Spread with mustard-mustard and sour cream, spread the leek mixture on top and mix with
Place in the oven (lowest shelf) and bake for about 15 minutes. If necessary, wash chives, shake dry and cut into small rolls. Sprinkle the finished tarte flambée with chives as desired and cut into 6 pieces.