Preheat the oven to 400°F. Spread bacon across bottom of a large 12-inch cast iron skillet, place over medium-low heat, and slowly cook, stirring frequently, until it has crisped, and fat has rendered out, about 8-10 minutes. Leave bacon drippings in pan.

Increase heat to medium, add 3 tablespoons butter, onion, and celery, and cook until vegetables are soft, 6-8 minutes. Add garlic and cook until aromatic, about 1 minute. Stir in crumbled cornbread and cook, gently stirring, until lightly browned, about 5 minutes. Remove from heat. Fold in sage, thyme, salt, and pepper.

In a large bowl, beat eggs until smooth. Whisk in stock and parsley. Fold into cornbread mixture in skillet until evenly combined. Top with remaining butter. Bake until the dressing is set and golden brown, about 45 minutes. Let sit for at least 10 minutes before serving.