Preheat oven to 370 degrees F. Grease an 8 x 8-inch casserole dish with foil. Spray with cooking spray or butter; set aside.
In a large bowl, mix together cornmeal, all-purpose flour, salt, baking soda, baking powder, and sugar.
In a medium bowl, whisk eggs. Pour in buttermilk and melted butter. Whisk to combine.
Slowly pour wet ingredients into dry ingredients, a little at a time, folding batter to incorporate. Repeat until all the wet ingredients are incorporated into the dry mixture.
Pour into prepared casserole dish.
Bake in oven 35-40 minutes. Top should be golden brown and center should be set, adjust time accordingly. Insert a toothpick into the center. If batter is wet, continue to bake at 5 minute intervals. If top gets too dark, cover with foil.
Cool cornbread completely then crumble into 1-inch cubes.
Preheat oven to 425°F. Lightly oil or butter an 8x8-inch baking dish or casserole dish or two pyrex round casserole dishes.
Heat oil in skillet over medium high heat. Cook sausage until deep golden brown in color. Remove meat.
Saute onion, green onions, and celery until translucent in color and fragrant; about 7 minutes. Stir in garlic and cook 1-2 minutes.
In a large mixing bowl, whisk eggs. Add chicken broth and melted butter, leaving about 2 tbsp melted butter for topping.
Whisk in sausage, sauted vegetables, chopped parsley, creole seasoning, salt, and pepper.
Fold in cornbread crumbles. Mix thouroughly.
Evenly spread cornbread dressing into prepared casserole dish. Pour on remaining butter.
Bake in oven for 45-50 minutes. Scrap and mix dressing every 25 minutes to prevent the bottom from burning.