How to Make It
Spread bread on 2 rimmed baking sheets in an even layer and set aside, uncovered at room temperature, overnight. (Alternately, toast bread in oven until dry and just barely starting to turn golden, 25–30 minutes. Let cool.)
Preheat oven to 350°F. Lightly butter a 9x13 or other 3-quart baking dish.
Melt half of butter in a large skillet over medium high. Add celery and onions and cook, stirring often, until softened, 6–8 minutes; season with 1 teaspoon salt and several grinds pepper. Add wine and cook, stirring often, until almost evaporated, about 2 minutes. Add sage and parsley and cook until liquid is evaporated, about 1 minute more.
Transfer vegetable mixture to your largest (we mean REALLY big) bowl. In a separate medium bowl, whisk broth and eggs together. Add bread to vegetables and pour egg mixture over; use your hands to toss gently to combine.
Transfer mixture to prepared baking dish and dot with remaining butter. Cover with foil and bake until warmed through and slightly puffed, 25–30 minutes. Increase oven to 425°F. Uncover stuffing and continue to bake until golden brown on top, 20–25 minutes more (for more color, pop under the broiler until toasted, 1–2 minutes). Top with celery leaves before serving.