Preheat the oven to 375 degrees Fahrenheit.
Break up a full, freshly baked pan of cornbread in a large bowl and set it aside.
Dice the celery and onions.
Melt the butter in a cast-iron skillet over medium heat and add the celery and onions. Let them cook until softened, and the onions start to turn translucent.
Add the garlic and cook for about another minute, just until fragrant. Set that vegetable mixture aside.
In a separate bowl, whisk together the eggs, heavy cream, sage, parsley, thyme, onion powder, kosher salt, white pepper, and chicken bouillon powder.
Pour the seasoned mixture into the bowl of cornbread and stir to evenly combine.
Add the cooked celery, onion, and garlic mixture and stir again.
Pour in the chicken stock and give everything one last good mix.
Spray a 9-by-13-inch baking dish with cooking spray, then pour in the cornbread dressing mixture.
Spread it out evenly and gently press it down across the dish.
Bake at 375 degrees for about 35 minutes, or until the center is set and the edges begin to turn golden.
If you want a little more color on top, switch the oven to broil on low — about 550 degrees — for a few minutes.
Remove it from the oven and let it rest for a few minutes before serving.