Bread - Preheat oven to 250F, cube the day old French bread into ½-inch cubes, place it on a baking sheet (or two baking sheets) and bake, stirring occasionally, until the bread is dried out, about 45 minutes. *Tips - You must begin with very dry bread or it’ll turn to mush. I use French bread that I purchase from my grocery store bakery. Italian bread or sourdough may be substituted. Do NOT use basic regular bread that you'd use for sandwiches or toast because it will disintegrate. Toast-Ahead - To save time on the day of, you can bake and dry out the bread the night before . Leave it uncovered on the counter until the morning or when you’re ready to make the stuffing.
Sauteeing - To a large skillet, add the butter, onions, celery, and saute over medium to medium-high heat for about 8-10 minutes, or until the vegetables are soft and just beginning to brown. In the final minute or two, add all the fresh herbs, salt, pepper, stir to combine, and saute to allow the flavors to bloom.
Slow Cooker - To the insert of your slow cooker, add the dried bread, the buttery vegetables and herbs mixture; stir to combine.
Add 1 ½ cups broth, stir to combine and coat everything evenly, place the lid on your slow cooker and cook on LOW for about 3-4 hours. Tip - I do not recommend using the high heat setting; low is better to cook the stuffing evenly and without drying it out. Stuffing is done when it's cooked through, lightly moist throughout - not still soggy but not overly dried out either. Slow cookers vary a lot, as does personal preference for stuffing. Keep an eye on yours and cook as needed, however long that takes.Additional Broth - During the slow cooking process, check on the stuffing, and use your judgment if you want to add additional broth or not, up to about 1 cup. If you like drier stuffing, you may not need to add any. If your bread was very dry or you like more moist stuffing, add some broth. It's really going to depend on your preferences as well as your ingredients as well as the heat output of your slow cooker.
Serving - Transfer stuffing to a serving bowl (or serve it straight from the slow cooker). Fluff it with a fork first before serving. You can garnish it with additional fresh herbs, if desired. You can make it about 3 hours ahead of time and use the keep warm feature to hold it. Any longer than that, it will start becoming dried out.
