Grease the crockpot with cooking spray.
In a large bowl, whisk together the eggs and milk until well combined.
Stir in salt and pepper to taste.
Add the diced bread, mixing gently to soak.
Fold in the cooked sausage or bacon, cheese, bell peppers, and onions.
Pour the mixture into the greased crockpot.
Cover and cook on low for 6-8 hours or high for 3-4 hours.
Check for doneness by inserting a toothpick; it should come out clean.
Once cooked, let it cool for a few minutes before slicing.
Serve warm and enjoy!