• Adjust oven racks to accommodate both baking dishes at the same time (one for the hens, one for the stuffing). Preheat oven to 350 degrees.

For the hens:

• Truss the hens by tucking the wings against the hens, running a piece of cooking twine from the neck of the bird around the breasts, and tie the drumsticks together.
• Place the hens breast side up in a shallow baking dish. Dry the hens with paper towel, then rub each hen with butter, and sprinkle with salt and freshly ground pepper. Bake uncovered for one hour.

For the stuffing:

• While the hens are baking, prepare the stuffing. Coat a 9-inch by 9-inch baking dish with butter.
• In large skillet over medium-high heat, melt butter until foaming. Add onion and celery and sauté until translucent, about 7 to 8 minutes. Meanwhile, in a large bowl whisk the egg. Stir in broth, 1/2 teaspoon salt, and 1/4 teaspoon pepper.
• To the skillet, add parsley, sage, thyme, and marjoram until fragrant, about 30 seconds. Transfer to the bowl with the eggs and mix well. Add bread cubes and toss to combine. Transfer to prepared baking dish.
• Cover tightly with foil and bake until mostly heated through, about 25 minutes. Remove foil and bake until crispy edges form, about 15 to 20 minutes longer. 

For the apple glaze:

• While the hens and stuffing bake, prepare the apple glaze in a small saucepan. Bring the apple cider to boil and cook until reduced by half (1 cup). Remove the saucepan from heat and stir in honey and Dijon mustard. Set aside 1/2 cup for serving.
• Brush hens with apple glaze and bake until a thermometer reads 170 degrees, about 25 to 35 minutes longer, basting with pan juices occasionally (if hens brown too quickly, cover the pan loosely with foil).
• Remove hens from oven, tent with foil, and let stand 10 minutes. Serve the hens with stuffing, passing the reserved apple glaze separately.