This Southern-style kitchen sink breakfast casserole is your go-to for cleaning out the fridge! Made with whatever you've got on hand-day-old biscuits, croissants or my favorite - sourdough bread, a handful of veggies that need to be used up, whatever random bits of cheese you have in that drawer, and crispy bacon or sausage. This oven-baked beauty is hearty, comforting, and endlessly customizable. You can prep it the night before and just pop it in the oven come morning. It's the kind of down-home, no-waste recipe that'll have everyone coming back for seconds! Serves 8.

slice of Kitchen Sink Breakfast Casserole on a white plate with baking dosh in background

My Love Affair with Breakfast Casseroles 😍

Listen, I know us Southerners love a casserole recipe. But in my opinion, breakfast casserole is the king of all casserole recipes....GIMMMMMEEEE!!

This recipe came about on a whim. I love making this either for a lazy weekend or an easy weeknight dinner, and eat the leftovers for breakfast (just straight up cold outta the fridge please). So on one particular night, I opened the fridge and cleaned it out, so to speak.

I had a couple of poor croissants that had seen better days, so that started the base of it. There was a little bit of spinach and onion leftover from a recipe earlier in the week that needed to be used up, and then we always have an assortment of cheese in the drawer, so I threw in handfuls of a couple of different kinds. Plus some bacon and the egg base, and whalaa - dinner was served.

This recipe serves as a base guideline for you. Use whatever bread, veggies, and cheese combo you have - unlike French toast casserole, there are no rules! This leftover buns casserole is just a little bit of this and a little bit of that. Use what you have. Nothing fancy or fussy, but it is destined to be yummy every single time.

ingredients needed for Kitchen Sink Breakfast Casserole

whisked eggs in a bowl — **STEP ONE:** In a large bowl, add the eggs, milk, salt, and pepper. Whisk until combined.

whisked eggs and veggies in a bowl — **STEP TWO:** Add in shredded cheese, and any meat and/or veggies you are using. Whisk well.

croissants torn up laying in a baking dish for Kitchen Sink Breakfast Casserole — **STEP THREE**: Roughly tear your bread and place it in the bottom of a greased baking pan.

Kitchen Sink Breakfast Casserole before going into the oven — **STEP FOUR:** Pour the egg mixture over the bread. Pat down the bread and make sure the egg mixture is evenly distributed over the whole pan. Place in a 350-degree oven and bake for 45-50 minutes and until set in the middle.

baked Kitchen Sink Breakfast Casserole in a clear baking dish — **STEP FIVE:** Remove from the oven and cool for 5-10 minutes. Slice and enjoy!

Prep Ahead

You know I love a prep-ahead kinda situation, and casserole recipes are perfect for that! If I know I want this on a Saturday morning, I will prep on Friday night before, so all I have to do is pop it in the oven and enjoy in my robe while I drink my coffee and become coherent 😉

Make the recipe according to the directions. Do not bake.
Wrap tightly in plastic wrap and store in the fridge overnight.
In the morning, place in a preheated oven and bake as directed.

slices out of Kitchen Sink Breakfast Casserole

Recipe