In a skillet over medium heat, melt 4 tablespoons of unsalted butter. Sauté chopped onion and chopped celery until softened, about 5 minutes. Stir in chopped pecans, fresh sage, thyme, kosher salt, and black pepper, cooking for another 2 minutes. Remove from heat and mix in cooked rice, diced Fuji apple, sweetened dried cranberries, and flat-leaf parsley, then set aside to cool.

In a saucepan, combine apple cider and maple syrup. Bring mixture to a gentle simmer over medium heat, stirring occasionally, until reduces to a syrupy consistency, about 10-15 minutes. Once thickened, whisk in Dijon mustard and ground cinnamon, ensuring all ingredients are well-combined. Set glaze aside for later.

Remove the giblets from Cornish hens and rinse under cold water. Pat dry with paper towels. Preheat oven to 425°F and prepare a roasting pan with a roasting rack.

Season inside cavities of each hen with kosher salt and black pepper. Fill cavities with prepared Apple-Cranberry rice stuffing, pack it loosely. Tie legs together with kitchen twine.

Brush outside of hens with melted butter and season with kosher salt and black pepper. Roast in preheated oven for 20 minutes, then reduce temperature to 375°F and continue roasting for 40-50 minutes, glazing every 10 minutes with apple cider glaze during last 30 minutes.

Use a meat thermometer to ensure the internal temperature reaches 180°F. Remove hens from oven and let rest for 10 minutes before serving.