Preheat your oven to 190°C (375°F) and set a roasting pan with a rack inside.
Pat the game hen dry with paper towels, then generously season the inside and outside with salt and pepper.
In a small bowl, combine cranberry sauce, orange zest, balsamic vinegar, and cinnamon. Stir until well blended to create your glaze.
Stuff the cavity of the hen with fresh thyme and orange slices to infuse aroma and flavor during roasting.
Place the game hen on the prepared rack in the roasting pan, breast side up, and brush generously with the cranberry-orange glaze.
Roast the game hen in the oven for about 1 hour, basting every 15 minutes with the glaze, until the skin is golden and crispy and the juices run clear when pierced.
Use a meat thermometer to check the internal temperature; it should reach 74°C (165°F) in the thickest part of the thigh.
Once done, remove the game hen from the oven and let it rest for 10 minutes to allow the juices to settle.
Carve the bird, then spoon any remaining glaze over the slices for a glossy, flavorful finish.
Arrange the carved pieces on a serving platter, garnished with extra orange slices and herbs for a festive presentation.
