In a large saucepan over medium heat, melt the butter until bubbly and hot.
Add the onion, celery, and mushrooms and saute until onions are translucent and mushrooms have released their liquid.
Stir in the parsley and remove from heat.
Mix the dried bread crumbs and seasoning. Pour the onion mixture over the bread crumbs and stir to mix.
Add the chicken broth and eggs to the mixture and toss lightly.
Place in the crockpot (do not pack) and cook on high for 4 hours or on low for 8 hours.
Tips for making the best crockpot stuffing recipe
Use fresh herbs if you can. I feel fresh gives the best flavor.
Take the time to use fresh mushrooms. Don't use canned mushrooms in this crock pot stuffing as they give a tinny flavor that is very unappealing.
The last hour of cook time, remove the crockpot lid and let the stuffing simmer and cook out some of the moisture.
Stir the stuffing a few times in that last hour. The heat from the crockpot is working on making crispy stuffing along the bottom and sides. When you stir it, the crispy part comes up towards the top and you can get more crispy stuffing!