In a large, resealable food storage bag, combine the balsamic vinegar, finely minced garlic, cranberry sauce, packed brown sugar, crushed red pepper flakes, salt to taste, and olive oil. Mix the ingredients together until the brown sugar is dissolved and well-combined. This aromatic marinade will both flavor and tenderize the ribeye roast.

Pierce the ribeye roast all over with a knife to help the marinade penetrate. Carefully place the roast into the bag with the marinade, seal it securely, and massage the marinade into the meat. Refrigerate the bag overnight, turning it occasionally to ensure all sides of the roast are evenly coated with the marinade.

Preheat your oven to 350°F (175°C). Remove the marinated ribeye roast from the bag and pat it dry with paper towels to remove any excess marinade—this helps achieve a good sear. Heat the vegetable oil in a large cast iron pan over medium heat. Once the oil is hot, add the roast and sear it until a deep golden-brown crust forms on all sides. Don't rush this part: a good sear means more flavor!

Pour the reserved marinade into the pan with the seared roast. Add the beef broth and stir to combine, scraping any browned bits from the bottom of the pan for extra flavor. Add the whole cranberries and fresh thyme sprigs to the pan. Transfer the entire pan to the preheated oven and roast for about 20 minutes per pound, or until a meat thermometer reads 140°F for medium-rare. I always recommend using a thermometer to ensure the perfect doneness.

Remove the pan from the oven and let the roast rest for 15 minutes before carving. Resting helps retain the juices, making the meat tender and flavorful. Slice the roast and serve with the cranberry-pan sauce spooned over the top. To make the dish even more delicious, I like to sprinkle a bit of extra fresh thyme just before serving.