Preheat your oven to 350°F (175°C). If your cornbread isn't already stale and somewhat dry, crumble it into a large bowl and spread it evenly on a baking sheet. Bake at 250°F (120°C) for 15-20 minutes, or until lightly dried, stirring once. This crucial initial drying step is key to preventing a soggy dressing and creating the perfect foundation for our desired texture.

While the cornbread dries or the oven preheats, melt the butter in a large skillet over medium heat. Add the chopped onion and celery. Cook, stirring occasionally, until softened, about 8-10 minutes. Stir in the fresh thyme, dried sage, salt, and black pepper. Cook for 1 minute more until fragrant.

Transfer the dried cornbread crumbs to a large mixing bowl. Add the cooked aromatic mixture. In a separate bowl, whisk the eggs lightly, then add them to the cornbread mixture. Gradually pour in 1 1/2 cups of the chicken broth, mixing gently with a spatula or your hands until the mixture is uniformly moist but not swimming in liquid. You want it to hold together when lightly squeezed. Add up to 1/2 cup more broth, if needed, to achieve this ideal moist consistency. This careful balance of liquid ensures a perfectly moist interior.

Lightly grease a 9x13 inch baking dish. Transfer the cornbread mixture into the prepared dish, spreading it evenly. Cover the baking dish tightly with aluminum foil. Bake for 30 minutes at 350°F (175°C). This covered bake is the absolute secret to locking in moisture and ensuring the inside cooks through beautifully without drying out, giving us that tender, succulent texture.

Remove the foil. Increase the oven temperature to 375°F (190°C). Bake for an additional 20-30 minutes, or until the top is deeply golden brown and deliciously crispy. This final uncovered bake is precisely how we develop that irresistible golden crunch, contrasting perfectly with the moist interior.

Let the dressing rest for 10 minutes before serving. Garnish with fresh thyme sprigs if desired. Enjoy that incredible texture!