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High Protein Crockpot Breakfast Casserole

Practical and dependable, this High Protein Crockpot Breakfast Casserole is designed to simplify busy mornings without skimping on flavor or nutrition. It’s a set-and-forget slow-cooker dish that yields a hearty, sliceable casserole packed with eggs, veggies, and turkey sausage for sustained energy. If you like make-ahead breakfasts that reheat well, you might also enjoy this savory twist on casseroles: a crockpot chicken enchilada casserole that’s similarly effortless.

Why make this recipe

If you’re tired of scrambled eggs that leave you hungry an hour later or breakfast routines that are chaotic on weekday mornings, this recipe is perfect because it cooks slowly while you sleep, produces servings that reheat easily, and delivers protein and veggies in every slice. The slow, gentle cooking helps the eggs set evenly without drying out, and the inclusion of turkey sausage (or bacon) boosts the protein so you stay fuller longer. It’s an ideal solution for meal-prepping breakfasts for the week, feeding a brunch crowd, or simply simplifying mornings without sacrificing taste.

Step-by-Step Guide to Making High Protein Crockpot Breakfast Casserole

Ingredients

12 large eggs
1 cup milk
2 cups chopped spinach
1 cup diced bell peppers
1 cup diced onions
2 cups cooked and crumbled turkey sausage or bacon
1 cup shredded cheese (cheddar or your choice)
Salt and pepper to taste

Overview of the method
This crockpot casserole is a layered, mixed egg bake that sets slowly. The key is to combine the eggs and milk thoroughly and to evenly distribute the vegetables, sausage, and cheese so every bite is balanced. Because slow-cooker heat varies, check the casserole toward the end of the cooking window so you don’t overcook it.

Detailed Steps

Prepare your ingredients. Chop the spinach, dice the bell peppers and onions, and cook and crumble the turkey sausage or bacon. Grate the cheese if not pre-shredded. Having everything ready keeps the assembly quick and clean.
In a large bowl, whisk together the eggs and milk until combined and slightly frothy. The whisking introduces a little air and helps create a light, uniform texture. Season with a pinch of salt and a few grinds of black pepper.
Stir in the spinach, bell peppers, onions, turkey sausage, and cheese. Mix just until everything is evenly distributed; avoid overmixing, which can break down the vegetables too much.
Grease the crockpot with cooking spray or a thin layer of butter. This prevents sticking and makes serving and cleanup easier. If your crockpot tends to run hot, consider lining it with a slow-cooker liner for an even easier cleanup.
Pour the egg mixture into the crockpot and spread it evenly. Tap the pot gently on the counter to release any large air pockets.
Cover and cook: set on low for 6–8 hours or high for 3–4 hours, until the eggs are set and the center is no longer jiggly. If using the low setting, cooking overnight can be convenient—just ensure your crockpot has an automatic warm function or that you’re home when cooking finishes.
Once cooked, turn off the crockpot and allow the casserole to rest for 10–15 minutes before slicing. The rest time helps the eggs firm up and makes for cleaner slices. Serve warm.

Concise Directions (as provided)

In a large bowl, whisk together the eggs and milk.
Stir in the spinach, bell peppers, onions, turkey sausage, cheese, salt, and pepper.
Grease the crockpot with cooking spray.
Pour the egg mixture into the crockpot.
Cover and cook on low for 6-8 hours or high for 3-4 hours, until the eggs are set.
Serve warm.

Why these ingredients work together

Eggs and milk provide the custardy base that sets into a tender, sliceable texture.
Spinach adds color, vitamins, and moisture while blending quietly into the custard.
Bell peppers and onions contribute crunch, sweetness, and savory depth when cooked slowly.
Turkey sausage (or bacon) supplies lean protein and savory flavor, keeping the casserole satisfying.
Cheese binds, browns slightly on top, and adds richness—cheddar is classic, but pepper jack or Gruyère are great swaps.

Best Way to Store High Protein Crockpot Breakfast Casserole

Refrigerate: Store leftover casserole in an airtight container in the fridge for up to 4 days at 4°C (40°F) or below.
Freeze: Portion into freezer-safe containers or wrap tightly in plastic and foil; freeze for up to 3 months at −18°C (0°F) or lower.
Reheat: Thaw overnight in the refrigerator if frozen; reheat individual slices in the microwave for 60–90 seconds or in a 180°C (350°F) oven for 10–15 minutes until heated through.

Serving Suggestions for High Protein Crockpot Breakfast Casserole

Serve slices warm with a side of fresh fruit or a simple mixed greens salad dressed with lemon and olive oil to balance the richness.
For a brunch spread, place the casserole on a platter with bowls of salsa, sour cream, and avocado slices so guests can customize each portion.
Turn leftovers into breakfast burritos: reheat a slice, crumble it, and wrap in a warm tortilla with extra cheese and hot sauce.
Add a dollop of Greek yogurt or a drizzle of pesto for a flavor lift when serving to guests.

Tips to Make High Protein Crockpot Breakfast Casserole

Use room-temperature eggs for a more even set—cold eggs can slow down cooking and cause uneven texture.
Squeeze excess moisture from thawed frozen spinach or very juicy bell peppers with a clean towel to avoid a watery casserole.
Precook and drain the turkey sausage or bacon thoroughly to prevent excess fat accumulating in the casserole; blot with paper towels as needed.
If your crockpot runs hot, check for doneness 30–45 minutes before the lower end of the cooking time. The center should be just set, not rubbery.
For easier serving, line the crockpot with parchment paper over the greased surface; lift the whole casserole out to slice on a cutting board.

Variations

Vegetarian swap (paragraph): For a meat-free version, skip the turkey sausage and increase the veggies—add 1 cup cooked mushrooms and 1 cup zucchini for extra texture, and consider stirring in ½ cup of crumbled feta for salty richness. This keeps the protein moderate while offering more produce; if you want higher plant protein, fold in 1 cup of cooked quinoa or a can of drained white beans mashed slightly before adding to the egg mix.
Cheese and herb twist (bulleted):
- Use pepper jack and cheddar blend with a tablespoon of chopped fresh chives for a subtle kick.
- Replace cheddar with Gruyère and add 1 teaspoon dried thyme for a nuttier, more aromatic profile.

FAQ
Q: How do I know when the casserole is fully cooked?
A: The center should be set and only slightly springy when gently pressed; there shouldn’t be any runny egg. If you have an instant-read thermometer, the internal temperature should reach 160°F (71°C).

Q: Can I prepare this the night before and cook it in the morning?
A: Yes. Assemble the casserole in the crockpot insert, cover, and keep refrigerated overnight. Remove the insert from the fridge about 30 minutes before placing it in the crockpot (if the insert is cold) and then cook as directed.

Q: What can I use instead of turkey sausage?
A: Substitute cooked, crumbled bacon, diced ham, or a plant-based sausage alternative. If using bacon, drain excess fat to avoid a greasy texture.

Q: Will this casserole stay moist if I cook on low for the full 8 hours?
A: Generally yes—crockpot cooking on low should keep the casserole moist. If concerned, use the low end of the suggested time and check doneness earlier. Overcooking can dry the eggs, especially in hotter models.

Q: Can I make this dairy-free?
A: Replace the milk with unsweetened almond milk or oat milk, and use a dairy-free cheese alternative. Flavor will be slightly different, but the texture remains similar.

Additional tips for flavor and nutrition balance

Add a tablespoon of Dijon mustard to the egg base for subtle tang that complements the sausage.
Fold in fresh herbs like parsley or basil just before serving to brighten the flavors.
For a lower-sodium version, use low-sodium turkey sausage and reduce added salt, relying on herbs and pepper for seasoning.

Meal-plan and timing strategies

Weekend batch-prep: Cook on low for 6–8 hours on a weekend morning, slice, and refrigerate portions for grab-and-go breakfasts during the week. Reheat in the microwave or toaster oven for quick meals.
Overnight option: If you want breakfast ready when you wake, set the crockpot to low and cook for 6–8 hours overnight, but ensure your slow cooker is in good condition and placed safely on a heatproof surface. Alternatively, use a programmable crockpot with delayed start features for precise timing.

Nutritional considerations
This casserole provides a strong protein punch thanks to 12 eggs and 2 cups of turkey sausage. The spinach and bell peppers contribute vitamins A and C plus fiber, while cheese adds calcium and fat for satiety. To reduce calories or fat, use lean turkey sausage and a reduced-fat cheese, or cut the cheese quantity to ¾ cup without sacrificing too much creaminess.

Troubleshooting common issues

If the casserole turns out too watery: Next time, reduce high-water vegetables (squeeze spinach, use less watery peppers) and ensure cooked meat is well-drained.
If it’s rubbery or overcooked: Shorten cooking time slightly or check for doneness earlier; different crockpots vary in heat output.
If it sticks: Always grease generously or use a liner; letting the casserole rest before serving also loosens it from the sides.

Quick reheating guide

Microwave: Reheat one slice for 60–90 seconds on high (cover loosely) or until heated through.
Oven/toaster oven: Heat at 180°C (350°F) for 10–15 minutes from refrigerated, longer if frozen and thawed. Cover with foil if the top is browning too quickly.

Final thoughts on prepping for different household sizes

Small households: Bake in a smaller slow cooker (2–3 quart), and reduce ingredients proportionally (e.g., halve the recipe).
Large families or gatherings: Double the recipe and use two crockpots or make two batches back-to-back; slices can be kept warm in a low oven (about 90–100°C / 200–210°F) for short serving windows.

Conclusion

This High Protein Crockpot Breakfast Casserole is a versatile, time-saving recipe that fits meal prep routines and busy households—perfect for anyone who wants a nutritious, protein-forward breakfast with minimal morning effort. For another slow-cooker breakfast idea that emphasizes wholesome ingredients and a simple method, check out the Healthy Slow Cooker Breakfast Casserole from Sweet Savory and Steph. If you’re looking for additional variations on the crockpot breakfast casserole theme with different flavor profiles and techniques, explore the Crockpot Breakfast Casserole guide from The Girl on Bloor.