Melt the butter in a frying pan.
Add the chicken livers; cook gently, turning occasionally, until the pink juices have just disappeared.
Sprinkle the livers with salt and pepper, and put into a very slow oven to keep warm while making the sauce.
To the pan in which the livers cooked, add the flour and stir until smooth over low heat.
Gradually add the chicken stock and cook 3 to 4 minutes to remove the raw taste of the flour.
Then add the wine.
As soon as the wine bubbles, add the sour cream and stir until smooth.
Do not allow to boil after this.
Taste for seasoning, adding salt if necessary.
Pour over the livers