Prep Bread: Lay slices of bread out on a baking tray to dry out for 1-2 days. Store in a cool dry place, lightly cover with paper towels. Or dry out in the oven, see recipe notes.
Soften Bread: Break up stale bread into 2 to 3-inch pieces as you add it to a large stock pot. Add eggs and water and gently use your hands to mix the bread with the water and the eggs, careful not to mix too much so that the bread starts to break down and becomes pasty, but instead just so that all of the bread is coated in some water or some egg. Once well coated, you can use your hands to break up the larger pieces into smaller pieces or whatever size desired. Let sit for 2-3 minutes to absorb until the bread has softened a bit.
Season: Once slightly softened, add salt, pepper, parsley, garlic powder, and sage to the stock pot and mix well.
Optional Onions: If adding onions, melt 2 tablespoons of butter over medium heat in an extra wide saute pan, at least 12 - 14 inches wide, or 3.5 quart skillet. Add onions and turn the heat down to medium-low. Saute slowly until the onions are translucent, 3-4 minutes. Remove from pan and set aside.
Cook Dressing: Add the rest of the butter to the skillet, turn the heat to medium, and melt the butter. Once melted, add the softened bread, flatten it to an even layer, and turn the heat down to medium-low. This is when you can also use a spatula to break up larger pieces of bread again, if desired. Let cook uncovered for 10-12 minutes or until the bottom of the dressing in the skillet has browned.
Flip: After 10-12 minutes, gently turn the dressing in the skillet so that the browned sides are facing up. Use a spatula to break up larger pieces of bread and let the other side of the bread brown and cook for another 10-12 minutes.
Final Cooking: Add sauteed onions (if using) to the pan and turn in the pan to cook with the bread and mix for final cooking, turning bread and pieces that are not browned to the bottom of the skillet to cook. You want a crispy outside of the bread with a tender center.
Serve immediately with your favorite holiday meal and gravy!