Crumble 8 cups baked cornbread into a large bowl. Add 2 cups diced celery and 3 cups diced yellow onion. Work at room temperature for 10 minutes while you fold gently with your hands. The crumbs should stay irregular with small and large pieces mixed together. (I tried finer crumbs first, the dressing became too dense.) Next, add 1 teaspoon rubbed sage and 2 teaspoons poultry seasoning. Use a folding motion until the herbs coat the crumbs evenly. You'll see green flecks spread through the golden mixture and smell the sage immediately. Miss this step and the flavor won't distribute evenly. Keep the crumbs loose before adding liquids because the texture depends on air pockets. Preheat the oven to 350°F now so it's fully hot by the time the pan goes in.

Pour 1/2 cup melted butter and 3 cups chicken broth over the cornbread mixture. Add 3 lightly beaten large eggs at 65°F room temperature. Fold with a rubber spatula using slow scooping motions for 3 to 5 minutes until everything feels evenly moistened. Then check the texture before baking. The mixture should look soft and damp but not watery. You'll notice the crumbs absorb the broth and the surface becomes slightly glossy. Add more broth too quickly and the dressing can turn soggy. Mix slowly because gentle folding keeps the baked texture tender.

Spread the moist dressing mixture into a greased 9x13 ceramic baking dish. Shape the surface loosely with a spatula and bake at 350°F for 30 minutes. Press lightly with the spatula in short strokes so the mixture fills the corners without becoming packed. After 30 minutes, the edges should begin setting while the center stays soft. You'll smell the herbs rising and see the top becoming slightly golden. Overpacking the dish makes the center heavy and prevents an even texture. Keep the layer even because steady heat creates a balanced crumb structure.

Continue baking the 9x13 ceramic baking dish at 350°F for 25 to 30 minutes. Rotate the dish halfway through and use a spatula to check the center gently. The top should develop golden patches while the inside stays moist and crumbly. Finally, remove the dressing when the edges look crisp and the center feels set. You'll hear a light crust when tapped and smell the toasted herbs. (My first batch baked at 375°F, the top browned before the center settled.) Bake until the structure sets because the eggs need time to bind the crumbs.