Cut the panettone into 3/4-inch squares and place in large bowl. Melt half of the butter in a saucepan over medium heat and continue to cook until light brown, about 5 minutes.
Take off the heat and add half the sage. Season with salt and pepper. Pour the sage butter over the bread and toss gently but swiftly. Spread out on 2 cooking sheets and place in the oven until light brown, about 15 minutes. Remove from the oven and place back into the bowl.
Meanwhile, place the dried fruit in a large bowl; add boiling water to cover and then set aside for at least 10 minutes. This will plump and soften the fruit for cooking. Drain fruit once plumped.
Raise the oven temperature to 375 degrees F.
Melt the remaining butter and add onion, celery, and carrot. Saute on medium-low heat until soft. Add dried fruit and remaining sage. Toss into cooled croutons. Gently toss and add chicken broth to moisten; add more broth if you like a softer stuffing. Stir in beaten eggs now, if using. Adjust salt and pepper, to your liking. Turn out into an oven-proof casserole.
Bake uncovered until golden brown on top, about 40 minutes.