Preheat the oven to 400°F.
Place squash in a roasting pan. Drizzle with 1 tablespoon olive oil, 1 teaspoon of salt, and ½ teaspoon of pepper. Mix to evenly coat the squash with the oil.
Spread wedges in an even layer to roast. Add the thyme sprigs. Roast in the preheated oven until the squash just begins to become tender, 20 minutes.
While the squash is roasting, prepare the tenderloin. In a small bowl combine the remaining spices: salt, pepper, garlic powder, onion powder, and cinnamon. Combine and evenly rub into the meat.
In a large skillet, heat the butter and remaining olive oil over medium-high heat. Once the oil/ butter is hot, sear the tenderloin until browned all around on all four sides, about 3-5 minutes. Remove from heat and set aside.
When the squash is just beginning to become tender, remove from the oven and add the apples. Stir apples and squash to lay evenly. Add seared tenderloin on top, adding any juice that gathered under the meat.
Continue to roast until the apples are tender and the pork registers 145°F, about 20-25 minutes. Remove from the oven and let rest for 10 minutes.
While pork is resting, prepare the pan sauce. Add apple cider to a skillet over medium-high for 2 minutes. Bring to a boil.
Turn down to a simmer. Once the apple cider is reduced by half, about 3 minutes, turn off the heat and whisk in the Dijon mustard and Grassland butter. Whisk until smooth.
Cut pork and pour the pan sauce over the cut pieces. Serve with the squash and apples.
