Here's a recipe for an easy breakfast casserole, you can make it ahead of time and bake it the next morning so it's perfect for Christmas morning. I've made this many, many times and it's a very forgiving recipe. I most often make it the night before and bake it the next morning as directed in the recipe, but I've also made it and baked it immediately-as long as you make sure all the bread gets saturated with the egg/milk mixture it'll be just fine. Instead of the green onions, I like to add a handful of onions and green peppers for a little extra flavor. You can also leave onions out entirely if that's your preference. I've tried it with all sorts of different bread, my favorite is to cut up half a loaf of Italian bread, but any bread will do. Leftovers also hold up well, just zap it for a couple minutes in the microwave and enjoy!
Here is the link for written instructions: https://www.laurainthekitchen.com/recipes/breakfast-casserole/