Preheat oven to 375℉.
Cut the Ciabatta Loaf into 1” cubes. Dry out the bread leaving the pieces out overnight, or bake for 5 minutes on a sheet tray in the 375℉ oven, then let cool.
Brown the mild Italian sausage in a large sauté pan over medium-high heat, and break into crumbles.
While the sausage is cooking, prepare the celery, large apple, fennel bulb, fennel fronds, onion, garlic, and thyme. Reduce the heat to medium, add the vegetables to the cooked sausage, and sauté for 10 minutes, until softened.
Add ½ cup of chicken stock to deglaze the pan and scrape the drippings into the mix, cooking until the chicken stock is evaporated. Season with salt and black pepper to taste.
Place the dressing mix into a large mixing bowl and add the Parmesan cheese, mixing thoroughly.
Add the dried bread pieces to the mixing bowl and incorporate.
Whisk the eggs and chicken stock in a medium mixing bowl and pour over the dressing, mixing thoroughly until the liquid is absorbed.
Spray a 13” x 9” casserole dish with oil and put the dressing into it. Let stand for at least 5 minutes.
Bake the dressing uncovered for 30 minutes.Remove the cover and bake for about 5 minutes, until the top is browned.
Once the dressing is cool enough to handle,garnish with the leftover fennel fronds, cut, and serve.