Prepare cornbread according to package instructions. Let cool completely. You can also use premade cornbread from the grocery store bakery, or your favorite recipe, as long as you end up with 2 (8-inch) squares. Cut cornbread into 1-inch cubes and spread out onto a baking sheet to dry out overnight.
Preheat oven to 375 degrees F and grease a 13x9-inch baking dish with butter or nonstick cooking spray.
Place cornbread chunks in a large mixing bowl and set aside.
In a large skillet over medium heat, melt butter. Add onion and celery and cook, stirring frequently, until soft; 7-8 minutes. Stir in garlic, sage and thyme and cook, stirring frequently, for 1 minutes. Pour in chicken broth and bring to a simmer for a few minutes. Remove from heat and ladle over the cornbread, tossing gently with each addition, until the cornbread is moist but not mushy. Add more chicken broth a little at a time as needed to moisten completely. Season with salt and pepper If desired (I recommend tasting first).
Spread cornbread mixture into the prepared baking dish and bake for 30 minutes, or until golden. Sprinkle with fresh minced parsley and serve.
Make Ahead of Time: Prepare the recipe as directed, then cover tightly and refrigerate up to 2 days in advance. Remove from the fridge and sit out for 30 minutes before baking.
Storage - Leftovers can be stored in the fridge, covered, or in an airtight container for up to 4 days.
Reheating - You can certainly reheat the leftovers in the microwave, but for best results, I recommend reheating in the oven at 350 until warm. You can cover it with foil to prevent over-browning.