for the Brine
In a small glass lasagna pan, dissolve all the ingredients and place the cleaned pork tenderloin, cover and refrigerate for about 3 hours. Remove from the brine and pat dry with paper towels.
for the Tenderloin, Preheat Oven 400°
Chop the walnuts into small pieces and add them to the sausage with cilantro, apricot, salt and pepper and mix well.
Using a boning knife butterfly the tenderloin be sure not to cut it all the way through. Using a plastic wrap, pound it until it is about ¼ of an inch thick. Salt and pepper and carefully cover the center of the tenderloin with an event thin layer of the sausage. Using the same technique as you would when you roll sushi carefully roll the tenderloin and using a butcher twine tie the entire tenderloin.
In a sauté pan, heat some olive oil. When hot, add the tenderloin and cook on all sides until golden brown. Place in oven and cook for about 8 minutes or until 140/145°.