If making your own bread cubes, dice a loaf of French bread into ½ inch cubes. Lay the cubes out on a sheet tray and let it sit out overnight. The bread will shrink overnight while it dries out, make sure you have about 14 cups of fresh cubed bread to make 12 cups of dried bread cubes.
In a large skillet over medium heat melt the butter, add the sausage, onion, celery, and garlic. Break up the sausage. Stirring occasionally, cook the mixture until the sausage is no longer pink and the veggies are soft, about 10 minutes.
Add the thyme, rosemary, salt, and pepper,
Stir to combine.
Spray your slow cooker with cooking spray. Measure out 12 cups of the bread cubes and add it to the slow cooker.
Add the sausage mixture on top. Whisk 2 cups of the stock with the eggs and pour it into the slow cooker.
Mix it well until combined. If the mixture looks dry, add a little more stock at a time until moistened, up to 1 more cup. You don’t want it very wet, just moistened. Stir well until combined.
Place a clean kitchen towel over the cooker and place the lid on top, this will help prevent excess moisture from getting into the stuffing.
Cook on low for 4 hours, stirring every 30 minutes, make sure to get the corners well to prevent sticking and burning.
If after 4 hours the stuffing seems a little wet, take the lid off and cook for an additional 30 minutes. Garnish with optional parsley and serve.