Spray a 6 quart slow cooker with cooking spray.
Melt the butter in a large frying pan. Add the onions, celery, and apples to the butter and season with salt and pepper. Sauté until the celery and onion are translucent, about five minutes. Mix in sage and thyme. Remove from the heat.
8 tablespoons unsalted butter, 1 medium yellow onion, 4 celery stalks, 2 small apples, 1/2 teaspoon kosher salt, 1/4 teaspoon black pepper, 1 teaspoon dried sage, 1 teaspoon dried thyme
In a separate pan, cook the sausage, breaking it up until no longer pink. Remove from the heat and drain the excess grease.
1 pound sweet Italian sausage
In the base of the slow cooker, coat the bread with the eggs. Mix in both the meat and the veggie butter mixture. Then mix in the cheese. Pour the chicken stock over it.
2 eggs, 8 cups dried French bread cubes, 1 cup grated parmesan cheese
Cook on low for 4 to 5 hours. (Read about how slow cookers vary here.)