High Protein Egg White Breakfast Casserole (Low Calorie, Veggie-Packed)
If you have ever tried to eat a high protein breakfast without feeling like you swallowed a brick, this egg white breakfast casserole is going to become your new best friend. It is light, fluffy, and genuinely satisfying without the calorie load that comes with a traditional egg casserole. We are talking roughly 180 calories per generous slice, over 25 grams of protein, and a serious hit of colourful vegetables that make every bite feel like a real meal. It is the kind of breakfast that keeps you focused and energised straight through to lunch, no mid-morning snack required.
The secret to keeping this casserole both low calorie and incredibly high in protein is the combination of liquid egg whites and low-fat cottage cheese. The cottage cheese blends completely into the egg white base, adding a creamy richness and a serious protein boost without adding much fat or sugar at all. Alongside that base, we load in crumbled turkey sausage, which gives you all the savoury, hearty flavour you want from a breakfast casserole without the saturated fat of a traditional pork sausage. Then comes the vegetable medley: spinach, red bell pepper, mushrooms, and spring onions. Each one adds fibre, colour, micronutrients, and genuine flavour. This is not a casserole where the vegetables disappear into the background. They are front and centre.
One of the things that makes this recipe so practical is how well it works for meal prep. You can bake the whole thing on a Sunday evening, slice it into eight portions, and have a ready-to-go high protein breakfast for the entire week. Just reheat a slice in the microwave for about ninety seconds and you are sorted. It holds its texture beautifully in the fridge, and the flavours actually deepen overnight as the herbs and vegetables settle into the egg white base. For busy mornings when the idea of cooking anything feels overwhelming, this casserole sitting in your fridge is genuinely a lifesaver. Wrap individual slices in foil and you can even take them on the go.
A few things worth noting before you start. Make sure you fully drain your mushrooms after cooking them in the pan. Mushrooms hold a lot of water and if you skip this step, that water releases into your casserole as it bakes, which can make the texture watery rather than fluffy. The same goes for the spinach. If you are using fresh spinach, wilt it in the same pan first and then squeeze out every bit of moisture you can. These two small steps make a huge difference in the final result. Season generously too. Egg whites on their own are quite bland, so you want the garlic, smoked paprika, and herbs to do some real work here. Taste your vegetable mixture before adding it to the egg whites and adjust accordingly. Once you get comfortable with the base recipe, you can swap in any vegetables you have on hand, making this one of the most flexible and forgiving recipes in your healthy breakfast rotation.
Ingredients
- 3 cups liquid egg whites (from a carton or approximately 20 large eggs separated)
- 1 cup low-fat cottage cheese (blended smooth for best texture)
- 300 g turkey sausage (casings removed and crumbled)
- 2 cups fresh baby spinach (wilted and moisture squeezed out thoroughly)
- 1 large red bell pepper (finely diced)
- 200 g white mushrooms (sliced thin, cooked and drained of liquid)
- 4 stalks spring onions (thinly sliced, green and white parts)
- 3 cloves garlic (minced)
- 1 tsp smoked paprika
- 1 tsp dried oregano
- 0.5 tsp onion powder
- 0.5 tsp fine sea salt (adjust to taste)
- 0.3 tsp black pepper (freshly ground)
- 0.5 cup reduced-fat feta cheese (crumbled, for topping)
- 1 tsp olive oil (for cooking the vegetables)
Instructions
- 1
Preheat your oven to 190 degrees Celsius (375 Fahrenheit). Lightly coat a 9x13 inch baking dish with non-stick cooking spray and set it aside.
Use a glass or ceramic baking dish for the most even cooking and easiest cleanup.
- 2
Heat the olive oil in a large non-stick skillet over medium heat. Add the crumbled turkey sausage and cook for 5 to 6 minutes, breaking it up as you go, until browned and cooked through. Use a slotted spoon to transfer it to a plate lined with paper towel to drain any excess fat.
Do not skip the paper towel step. Draining the sausage keeps the calorie count lean and the casserole texture firm.
- 3
In the same skillet, add the diced red bell pepper and cook for 2 minutes until slightly softened. Add the mushrooms and garlic, cooking for another 4 minutes until the mushrooms are golden and most of their liquid has evaporated. Add the fresh spinach and stir for 1 minute until fully wilted. Remove the pan from the heat and allow the vegetable mixture to cool slightly, then press it in a clean kitchen towel or several layers of paper towel to remove as much moisture as possible.
Removing moisture from the vegetables is the single most important step for a fluffy, non-watery casserole.
- 4
In a blender or using a hand blender, blitz the cottage cheese until completely smooth. This takes about 30 seconds and eliminates any grainy texture in the finished casserole.
If you do not have a blender, whisk the cottage cheese very vigorously with a fork until as smooth as possible.
- 5
In a large mixing bowl, combine the liquid egg whites and the blended cottage cheese. Whisk together until fully incorporated. Add the smoked paprika, dried oregano, onion powder, salt, and black pepper. Whisk once more until evenly seasoned.
- 6
Scatter the cooked turkey sausage and the drained vegetable mixture evenly across the bottom of the prepared baking dish. Pour the egg white and cottage cheese mixture over the top, ensuring it flows down around all the fillings. Give the dish a gentle shake to settle everything evenly.
Use a spatula to gently push any vegetables that float to the top back down into the mixture so they distribute evenly.
- 7
Scatter the crumbled reduced-fat feta evenly over the top of the casserole. Finish with the sliced spring onions.
- 8
Bake uncovered in the preheated oven for 35 to 40 minutes, until the centre is fully set and no longer jiggles when you gently shake the dish. The top should be lightly golden. Remove from the oven and allow the casserole to rest for 5 minutes before slicing into 8 portions and serving.
Insert a clean knife into the centre. If it comes out clean with no wet egg mixture clinging to it, the casserole is done.
Nutrition per serving
180kcal
Calories
26g
Protein
6g
Carbs
5g
Fat
1.5g
Fibre
3g
Sugar
480mg
Sodium
Pro Tips
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Always drain your cooked mushrooms and squeezed spinach thoroughly. Excess moisture is the enemy of a firm, fluffy egg white casserole.
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Blending the cottage cheese smooth before adding it to the egg whites ensures a creamy, uniform texture with no lumps.
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Let the casserole rest for at least 5 minutes after baking before slicing. This allows the protein structure to firm up and makes clean slicing much easier.
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Season the egg white base generously. Egg whites are naturally mild, so the spices and salt need to work harder to bring flavour to every bite.
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For a golden, slightly crispier top, switch your oven to the grill or broil setting for the final 2 to 3 minutes of cooking.
Frequently Asked Questions
Variations
- •
Mediterranean Style
Swap the turkey sausage for diced chicken breast, replace the mushrooms with sun-dried tomatoes and olives, and use crumbled low-fat feta with fresh basil scattered over the top before baking.
- •
Southwest Spiced
Add black beans, corn kernels, diced jalapeño, and cumin to the vegetable mixture. Replace the feta with a small amount of reduced-fat cheddar and serve with a spoonful of plain Greek yogurt and fresh salsa on the side.
- •
Dairy-Free Version
Replace the cottage cheese with an equal amount of silken tofu blended completely smooth. Skip the feta topping or use a dairy-free alternative. The protein and texture remain excellent without any dairy.
- •
Greek Yogurt Boost
Stir 100g of plain non-fat Greek yogurt directly into the egg white and cottage cheese base alongside the cottage cheese. This adds even more protein and gives the casserole an extra creamy, slightly tangy quality.
Substitutions
- •Turkey sausage → Chicken sausage or lean ground turkey (Brown the ground turkey with the same seasonings as you would the sausage for full flavour.)
- •Low-fat cottage cheese → Plain non-fat Greek yogurt (Use the same quantity and blend smooth. Greek yogurt adds a slightly tangier flavour but keeps the protein content equally high.)
- •Red bell pepper → Yellow or orange bell pepper (Any colour bell pepper works well here. Green bell pepper is slightly more bitter but still delicious.)
- •Reduced-fat feta → Reduced-fat goat cheese or part-skim mozzarella (Goat cheese adds a creamier tang. Mozzarella gives a milder, meltier topping.)
- •Fresh baby spinach → Frozen chopped spinach (Thaw completely and squeeze out every drop of water before adding. Frozen spinach works just as well and is often more economical.)
🧊 Storage
Store cooled, sliced casserole in airtight containers in the refrigerator for up to 5 days. For longer storage, freeze individual wrapped portions for up to 2 months. Reheat in the microwave for 90 seconds or in an oven at 180 degrees Celsius for 10 minutes until heated through.
📅 Make Ahead
This casserole is ideal for Sunday meal prep. You can also prepare the vegetable and sausage filling up to 2 days in advance and store it covered in the fridge. When ready to bake, simply whisk the egg white base, combine everything, and bake as directed. The fully assembled unbaked casserole can be refrigerated overnight and baked fresh the next morning.
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