Preheat your oven to 350°F (175°C). Grease a casserole dish with butter or cooking spray. Cut sourdough bread into cubes and layer in the bottom of the dish.

In a skillet over medium heat, add olive oil and sauté chopped mushrooms and chard for about 5-7 minutes until softened. Cool slightly, then layer on bread in the casserole dish.

In a bowl, whisk together eggs, milk, salt, and black pepper until combined. Pour egg mixture over the layered bread and vegetables.

Sprinkle shredded cheese over the top and add cherries or any sweet topping of your choice.

Cover with plastic wrap or a lid and refrigerate overnight to allow the bread to absorb the egg mixture.

On Christmas morning, preheat the oven to 350°F (175°C). Remove cover and bake for 35-40 minutes until golden brown.