Pre-heat the oven to 375 degrees, and butter a 9x13 inch baking dish or casserole pan.
Cube up your loaf of bread into 1-2 inch cubes. Toss them onto 2 sheet trays and toast in the oven at 375 degrees for about 10-15 minutes until lightly golden. While the bread toasts, you can prepare the rest of the stuffing.
Melt the butter into a large, high walled skillet or soup pot. Saute the onion and celery in the friendly fat for about 5-7 minutes. Add a few pinches of salt to bring out their juices and sweeten.
Add the garlic, sage, thyme, and parsley, and cook for a minute.
Add the broth and bring to a simmer. Taste for seasoning/saltiness and add as needed. It should taste like a salty herbed soup. This is what will be seasoning the bread, so you want it to be quite flavorful.
Put your toasted bread cubes in a large mixing bowl, along with the eggs, and stir to combine. Add the seasoned broth to the mixing bowl, and stir to combine.
Pour the bread/broth mixture into the buttered 9x13 baking dish, and bake COVERED for 30 minutes at 375 degrees. You can use a lid if your casserole pan has a lid, or use foil. Uncover the baking dish and bake another 25-30 minutes, until the center is set, and the top is golden brown.