Melt butter at low heat and add the leek sliced very tinly

Once the leek wilted add raisins and pine kernels

cut the liver in slices and dust them with flour. Add to the pan with all the other ingredients and cook for a while.

Add the balsamic vinegar and the red wine. Nutmeg, salt and pepper.

Wait for the sauce to thicken.

If the liver is already cooked but the sauce is not thick enough remove the liver and allow the sauce to thicken.