Preheat your oven to 425°F.
Season the pork chop generously with salt, black pepper, and garlic powder on both sides.
In a small saucepan over medium heat, combine apple cider, brown sugar, and cinnamon. Bring to a gentle simmer and allow it to reduce by about half until slightly thickened. Remove from heat and set aside.
On a rimmed baking sheet, toss the halved Brussels sprouts with olive oil, salt, and pepper. Spread them out in a single layer.
Place the pork chop on the baking sheet alongside the Brussels sprouts.
Roast in the oven for 18-22 minutes, turning the Brussels sprouts halfway through, until the pork chop reaches an internal temperature of 145°F and the Brussels sprouts are tender and slightly crispy.
In the last few minutes of cooking, brush the pork chop generously with the apple-cider glaze.
Remove from the oven, let the pork chop rest for 3-5 minutes, then drizzle any remaining glaze over the top. Serve the pork chop with the roasted Brussels sprouts on the side.