Spread day-old bread cubes evenly on a baking sheet and toast in a preheated oven at 300°F (150°C) for 10-12 minutes.

In a large skillet, melt unsalted butter over medium heat. Add onion, celery, and garlic. Sauté for 6-8 minutes until softened.

Combine toasted bread cubes, sautéed vegetables, poultry seasoning, salt, pepper, parsley, and Parmesan cheese in a mixing bowl. Add eggs and broth until moist but not soggy.

With damp hands, scoop portions of the mixture and shape into balls. Place on a greased or parchment-lined baking sheet.

Preheat oven to 375°F (190°C) and bake the stuffing balls for 20-25 minutes until golden brown and crispy.

Remove from oven, let cool for a few minutes, then serve warm with gravy or cranberry sauce.