Layer it. Preheat the oven to 400 °F. Then turn on the stovetop medium-low and let the cast iron skillet heat up evenly. Add oil to the hot skillet and pour in one cup of sourdough starter. You will hear a nice sizzling sound. Sprinkle some salt on top of the sourdough starter as needed. Next, break four eggs right on top of the sourdough starter one by one.
Season it. Then, take a knife or fork and scramble eggs on top of the sourdough starter in the skillet. Make sure not to poke inside the dough much. Season eggs with salt and pepper to taste. Use less salt than usual since cheese is a salty ingredient. Sprinkle onion and garlic powder on top of the scrambled eggs.
Cheese and garnish it. Layer thin slices of cheddar cheese on top of the eggs. Sprinkle some sesame seeds on top for garnish.
Bake and serve it. Bake it uncovered until the cheese is bubbly and golden brown. Do not overbake the casserole. It will continue cooking while cooling off on a hot cast iron skillet. Serve with your favorite sides, and enjoy!
Notes
Tips
Feed your sourdough starter. Feed it the night before, so it will be bubbly and ready to use in the morning.
Use baking soda. You do not need to add baking soda if you use an active sourdough starter. Add baking soda to the flat sourdough discard. Mix 1/4 of baking soda per cup of sourdough then pour it into the skillet. This will result in a fluffy crust.
Use a thick sourdough starter. Thick sourdough starter consistency rather than a runny consistency works better.
Use a cast iron skillet. If possible, use a cast-iron skillet to make this dish. It will result in even cooking and a nicer, crispy crust. And, of course, keeps your food warm longer.
Adjust cooking time. Depending on your skillet, adjust for cooking time. This recipe will cook faster in a wider and open skillet.
Substitutions and variations
Substitute sourdough starterwith any bread. You can easily substitute sourdough starter with whatever bread you have on hand. Slice the bread and layer them on your baking dish and follow the rest of the recipe instructions. Adjust for cooking time. It will cook faster.
Substitute cheddar cheese. Use your favorite cheese. Either shredded or sliced works.
Replace eggs. Replace or add on other cooked proteins like chopped or ground chicken, turkey, and beef. Also, sausages, fish fillets, beans, or other legumes work too.
Substitute onion powder and garlic powder. Use finely chopped onion, garlic, peppers, broccoli, tomatoes, or other vegetables. Remove their excess liquid, and sauté them for the best result. Less liquid results in a fluffier crust. Add them to the top of the eggs before adding the layer of cheese.
Use other spices and herbs. Add your favorite spices and herbs to the dish to customize the flavor to your preferences; e.g. cayenne pepper, cumin, turmeric, basil, rosemary, thyme, or Italian seasonings.
Make the casserole crust thin. Use less sourdough starter ( 1/2 cup instead of 1 cup) as you wish. But make sure to adjust for cooking time. It will bake faster.
Equipment
I used an 8-inch cast-iron skillet to bake the sourdough breakfast recipe. Everything tastes extra delicious when cooked in cast-iron cookware.
Storage and reheat
Store this sourdough breakfast recipe in an air-tight container for up to 3 days in a fridge. Whenever ready to serve it, let it heat up slowly on a stovetop or microwave for a few seconds. You can freeze it in a freezer-safe bag for up to 3 months. Thaw it in the fridge the night before and heat it the same way.
How to serve it
Serve this sourdough breakfast recipe with a bowl of sweet fruit salad. Or serve it with avocado and tomato slices. I served it with sweet green grapes.