For the Cornbread:

1. Step 1: Preheat the Oven: Initiate the process by setting the oven to a temperature of 350 degrees Fahrenheit.
2. Step 2: Prepare the Batter: In a mixing bowl, combine one cup of self-rising cornmeal with half a cup of self-rising flour, three-quarters of a cup of buttermilk, two beaten eggs, and two tablespoons of vegetable oil. Stir these ingredients until well mixed.
3. Step 3: Bake the Cornbread: Pour the batter into a greased shallow baking dish. Place in the oven and bake for approximately 20 to 25 minutes, or until the cornbread is golden and cooked through. Remove from the oven and allow to cool completely.

For the Dressing:

1. Step 1: Preparation of Ingredients: Preheat the oven to 350 degrees Fahrenheit for the second time.
2. Step 2: Combine Dry Ingredients: In a large bowl, crumble the cooled cornbread, tear the dried white bread into small pieces, and crumble the saltine crackers. Set this mixture aside.
3. Step 3: Cook the Vegetables: In a large skillet, melt eight tablespoons of butter over medium heat. Add the chopped celery and onion to the skillet and cook until they are transparent, which should take approximately 5 to 10 minutes.
4. Step 4: Combine with Dry Mixture: Transfer the cooked celery and onion to the bowl containing the breads and crackers. Pour in seven cups of chicken stock and mix thoroughly. Taste and season with salt, freshly ground black pepper, optional sage, and optional poultry seasoning as desired.
5. Step 5: Add Eggs and Bake: Incorporate five beaten eggs into the mixture, ensuring everything is well combined. Transfer the mixture into a greased baking dish.
6. Step 6: Final Baking: Place the dish in the oven and bake for 45 to 60 minutes, or until the dressing is thoroughly cooked and has a golden brown crust on top.