1. Preheat your oven to 400°F (200°C). Pat the pork tenderloin dry with paper towels and season it generously with salt and pepper.
2. In a large ovenproof skillet, heat the olive oil over medium-high heat. Add the pork and sear it on all sides until golden brown, about 8 minutes. Transfer the pork to a plate.
3. In the same skillet, add the sliced apples, onion, and minced garlic. Sauté until the onion becomes translucent and the apples start to soften, about 5 minutes.
4. Stir in the chicken broth, apple cider, Dijon mustard, and fresh thyme. Bring the mixture to a simmer, scraping up any browned bits from the bottom of the skillet.
5. Return the pork to the skillet, nestling it among the apple and onion mixture. Transfer the skillet to the preheated oven and roast for 20-25 minutes, or until the pork reaches an internal temperature of 145°F (63°C).
6. Remove the skillet from the oven and transfer the pork to a cutting board to rest for at least 5 minutes.
7. Meanwhile, place the skillet back on the stovetop over medium heat. In a small bowl, mix the butter and flour to form a paste. Stir this into the skillet to thicken the gravy, cooking for another 2-3 minutes.
8. Slice the pork and serve it topped with the apple, onion, and garlic gravy, savoring every bite.

Cooking this dish always reminds me of patience and the joy of waiting for flavors to meld, a lesson I carry from my grandmother’s kitchen to my own.