Preheat oven to 350 degrees. Coat a large Dutch oven with cooking spray.
Place the pork tenderloin on a cutting board. Trim any fat from the meat then remove the silverskin (click here for instructions). Using a very sharp knife make a lengthwise cut down the center of the pork tenderloin, cutting to but not through the other side. Spread the meat open and place a piece of plastic wrap over the top. Working from the center to the edges, pound lightly with the flat side of a meat mallet to form a rectangle.
In a large skillet, cook the bacon until crisp, remove and place on a paper towel; crumble. Add the shallot and mushrooms to the skillet and cook, stirring occasionally, for 4-5 minutes. Add the garlic then cook, stirring constantly, for 1 minute. Stir in the bread crumbs, chicken broth, parsley, basil, sea salt, and freshly cracked pepper, to taste. Mix until well combined.
Rub the entire pork tenderloin with a drizzle of olive oil. Combine the porcini powder, ground fennel, sea salt, and freshly cracked pepper together until well combined. Rub over both sides of the tenderloin. Spread the stuffing mixture down the center of the tenderloin.
Roll up jelly-roll style. Use toothpicks or baker twine to seal together.
Heat the prepared large Dutch oven over medium-high heat. Place the stuffed pork tenderloin in the pan and cook for 4-5 minutes or until golden brown. Flip the pork over and place it in the oven for 25-30 minutes, or until the pork reaches an internal temperature of 160 degrees.
Remove from the oven and let the meat rest for at least 5 minutes before slicing and serving. Enjoy.