In a large bowl or stand mixer, combine the ricotta, Parmesan, mozzarella, thyme, oregano, garlic, salt and black pepper. Gently mix until very well combined. Taste mixture and add more salt if needed—some ricotta tastes saltier than others. Cover mixture and place in the refrigerator. Take your pork loin and, with shallow cuts, slowly roll it out until it is a flat piece of meat. Spread the cheese mixture on the rolled out loin, leaving about an inch border on all sides. Next lay the basil leaves on the cheese. Be sure to place the basil in an even pattern, covering as much of the cheese as possible. Now very gently, and not very tightly, roll the loin up. Take your time, and try to keep everything as even as possible. Once it is rolled together, you can either use toothpicks to pin the loin together or use butchers twine to tie it up. If you use toothpicks, count how many you use and ensure that many are found before you slice and serve.
The steps above can be done the night before cooking if you need to. Just be sure to chill in the refrigerator.
Preheat pellet grill to 250 to 275 degrees.
Place loin on the Silverbac or Grilla and cook for an hour. After an hour start checking the internal temp of the meat. At this point the meat should be reading about 100 degrees.
Let cook another 45min and check again. You want all the layers of meat and the entire length of the loin to read at least 140 degrees. You do not want to cook the loin past 150 degrees because it will start to dry out. 145 degrees is perfect.
Remove the loin from the Grilla Grill and rest in a large pan. While it is resting, place the marinara in a saucepan and bring just to a boil. You just want the sauce hot.
Slice the loin and remove the butchers twine or toothpicks. Lean the loin slices at a slight angle shingled against one another and top with the sauce. Use all the sauce and serve.