1. Spinach: In a large pan with a lid over medium heat, add the butter; when warm, add the shallots and sauté for about 2-3 minutes, or until they just begin to soften. Add the spinach, toss, then cover with the lid and cook for 2-3 minutes.
2. Remove the lid and turn the heat to medium-high. Toss the spinach for another 1-2 minutes until the greens are wilted. Season with salt and 4-5 twists of pepper.
3. Remove the spinach from pan and place in a colander lined with a clean kitchen towel. Allow the spinach to cool slightly, Twist the spinach in the towel and using your hands squeeze out any excess water. Then chop then spinach finely and set aside.
4. Pre heat the oven to 400º F.
5. Pork: Place one of the pork tenderloins onto a cutting board. Slip your boning knife under the shiny silver skin and remove it from the meat. There is no need to remove the little bits of fat.
6. Holding the knife parallel to the tenderloin, make a cut though the center, but not going all the way though to the other side. The pork will fold open like a book. Flip the meat over and place a piece of plastic wrap on top and gently pound the tenderloin out until you reach an over all thickness of ¼ inch. Set aside and repeat to the other tenderloin.
7. Lay the pounded tenderloin back on the cutting board. Place 5 of the prosciutto slices on top of the pork, over lapping slightly as you go.
8. Place one half of the spinach mixture evenly down the center of the loin; top with one half of the cheese.
9. Carefully roll the tenderloin up. Use butcher twine to secure it closed. Repeat with other tenderloin. Season the outside with salt & pepper.
10. Place a large ovenproof skillet on the stove on medium-high heat. Add the 3 tablespoons of olive oil. Once the oil is very hot, add the tenderloins. Sear each side of tenderloin until golden brown; about 2-3 minutes a side.
11. Carefully place the skillet into the 400º F oven and roast until the internal temperature reaches135-140º F inside, about 15-20 minutes, depending on the thickness of the tenderloin.
12. Transfer the meat to a carving board; loosely tent with aluminum foil and let rest for 10-15 minutes.
13. While the meat is rest place the pan on the stove over medium -high heat. CAREFUL THE HANDLE IS HOT!! Add the chicken stock and deglaze the pan scraping the bottom to get all the brown bits. Set aside.
14. Remove the string and slicing the tenderloin, place on a plate or platter. Spoon the pan sauce on top of the meat. Serve with the dauphinious potatoes.
TIPS & TRICKS
• Spinach can be sautéed a day or 2 in advance.
• The pork can be pounded the day ahead then assembled early in the morning of your party. Wrap the stuffed tenderloin in plastic or parchment. Pat dry with paper towels before searing to insure you get a beautiful brown sear.
• Left over pork makes a great lunch or sandwich.