Prepare the pork tenderloin for stuffing by butterflying it down the middle.
Prepare the brine solution by combining the garlic cloves, sea salt, peppercorns, cumin seed, coriander seed and bay leaves in a plastic zip top baggie. Add the pork tenderloin to the bag and fill with water so the meat is covered. Seal the bag and place in a dish or large bowl. Refrigerate for 1-4 hours. [Note: you can certainly skip the brining process but the meat may not be as tender.]
Rehydrate the dried figs by placing them in a bowl or measuring cup and covering with boiling water. Let sit for 10-15 minutes or until softened.
While the figs rehydrate, chop the mushrooms and mince the garlic and rosemary.
Heat a large skillet on high, add a spoonful of your fat of choice, and sauté the mushrooms with a pinch of salt until browned and cooked through [hint: use a large enough pan to avoid overcrowding the mushrooms which will make them soggy.]
When the mushrooms are nearly done, add the garlic and rosemary and cook for about 30 seconds. Turn off the heat. Drain the water off the rehydrated figs, chop them, and add to the mushroom mixture.
If you brined the meat, remove from the bag and pat the tenderloin dry with a paper towel (it’s okay if some spices stick to the meat). Lay the butterflied tenderloin flat and place the stuffing mixture on top. You may have extra depending on the size of the meat. Fold the edges of the meat over and secure with several toothpicks (see pictures).
Preheat the oven to 375 degrees F (190C).
Heat a large skillet on high (I used cast iron because it can go right into the oven but you can brown the tenderloin in a skillet and transfer to an oven-safe dish to finish the cooking). Add a spoonful of fat and sear the outside of the meat for about 4-5 minutes on one side. Flip and sear the other side to create a nice crust. Transfer the meat to the oven and bake for about 45 minutes or until a meat thermometer reads about 145 degrees F (63C).
Let the meat rest for about 10 minutes before slicing. You can also add a bit of water to the iron skillet, place it on the stove and loosen the caramelized bits of meaty goodness with a spatula or whisk for a quick pan sauce.