In a large skillet over medium heat, melt the butter and add chopped onion. Sauté for about 5 minutes, or until translucent. Add garlic and cook for another minute until fragrant.
Toss in the diced apple and cook for 3-4 minutes until slightly softened. Stir in the cranberries, nuts (if using), rosemary, thyme, cinnamon, salt, and pepper. Let everything cook for another minute, then remove from heat.
Add breadcrumbs and chicken broth to the pan, mixing until everything holds together loosely. It should be moist but not soggy—think stuffing consistency. Add more broth by the tablespoon if it's too dry. Set aside to cool slightly.
Butterfly and Season the Pork
Place your pork tenderloin on a cutting board. Use a sharp knife to butterfly it: slice horizontally down the length of the tenderloin, but don’t cut all the way through—leave about ½ inch attached. Open the tenderloin like a book and flatten it out with a meat mallet or the bottom of a heavy pan, aiming for an even thickness of about ¾ inch.
Season both sides generously with salt and pepper.
Fill and Roll
Spread the apple-cranberry filling evenly over the butterflied tenderloin, leaving a small border around the edges. Carefully roll the pork back up lengthwise like a jelly roll.
Secure the roll by tying it with kitchen twine at 1-2 inch intervals.
Sear the Pork
Preheat your oven to 375°F (190°C).
In a large oven-safe skillet, heat olive oil over medium-high heat. Sear the pork roll on all sides until golden brown—this helps lock in moisture and adds a beautiful crust.
Optional Glaze
If you’re using the maple-Dijon glaze, mix the two ingredients and brush the pork with half of it before it goes into the oven. Save the rest to glaze during the last 10 minutes of roasting.
Roast
Transfer the skillet (or place the pork in a roasting pan) to the oven. Roast for about 30–35 minutes, or until the internal temperature reads 145°F (63°C) in the thickest part.
Rest the pork for 10 minutes before slicing. This step helps redistribute the juices, keeping the meat tender and flavorful.