Preheat the oven to 400°F (200°C). Lightly grease a large roasting pan or Dutch oven.
Add the softened butter, olive oil, smoked paprika, black pepper, garlic powder, and dried thyme to a small bowl. Stir until smooth and thoroughly combined.
Pat the chicken completely dry. Carefully loosen the skin with your fingers, then spread the seasoned butter over the chicken and underneath the skin.
Place the chicken breast-side up in the prepared roasting pan. Tie the legs together with kitchen twine if desired.
Arrange the crushed garlic, onions, and lemons inside the chicken cavity and around the roasting pan. Pour the chicken stock around the chicken.
Transfer the chicken to the oven. Roast for approximately 1½ hours, adjusting the cooking time according to the size of your chicken. Periodically spoon some of the pan juices over the chicken.
Meanwhile, prepare the glaze. Add the maple syrup, cranberries, cranberry juice, and optional red pepper flakes to a saucepan over medium-high heat. Season with a small pinch each of salt and black pepper.
Bring the mixture to a gentle boil for 1–2 minutes. Reduce the heat and simmer for another 1–2 minutes, until the cranberries begin to soften and the glaze becomes slightly syrupy.
During the latter part of roasting, brush about half of the cranberry-maple mixture generously over the chicken. Continue roasting.
During the final 10 minutes, brush the remaining glaze over your Cranberry Maple Roast Chicken for a glossy, deeply flavored finish.
Continue cooking until the thickest part of the chicken reaches a safe internal temperature of 165°F (74°C), checking away from the bone.
Remove the chicken from the oven and allow it to rest for approximately 15–20 minutes before carving. Spoon extra cranberry glaze and pan juices over each serving.