Put the liver on a board, remove the valvelike parts, cut into narrow strips and sprinkle them with pepper.
Put these strips with a little olive oil in a heavy pan, sprinkle with the herbs and gently simmer. Add the chopped parsley, sliced garlic and salt, but only when you have turned the strips of liver. Mix the mustard with the juices released in the pan. Then pour in the red wine and raise the heat a little to hasten evaporation and the resulting cohesion into a sauce. The time taken: not more than 8 minutes. Serve on its own with a dish of patates vìdues to follow.