Preheat oven to 400 degrees F. Spray a muffin tin with non-stick spray. Chop up the fully cooked turkey sausage and divide between the muffin cups. Set aside.: When you start, your kitchen will smell faintly warm from the oven as it comes to temperature, and the sprayed tin should shimmer slightly under the light, signaling it is ready. Chopping the turkey sausage links into uniform pieces ensures each bite gets balanced flavor and makes portioning smoother. Place a few pieces in each cup so they sit comfortably at the bottom, which encourages a crisp edge where the meat meets the tin. A common mistake is leaving large uneven chunks that can create hollow pockets or prevent the egg mixture from settling evenly, so aim for consistent sizes. Visual cues to watch for are evenly distributed sausage and a clean, lightly oiled tin surface to prevent sticking, which helps with neat removal later.
Combine the whole eggs, egg whites, cottage cheese, 1/4 cup of cheddar cheese, salt, pepper, garlic powder and onion powder in a blender and process until smooth, should only take a few pulses.: As you blend, you will hear the motor change pitch as the curds of cottage cheese break down and the mixture becomes glossy. This smoothness is important because it creates that custard like, silky interior once baked. The tiny bits of cheddar cheese folded in add depth without making the batter grainy, so pulse just enough to combine. Overworking at high speed can build heat and introduce air, which may create unwanted pockets while baking, so use short pulses and check texture visually. A correctly processed mix will look homogenous, with no visible curds, and will pour smoothly from the blender, which is your cue that it is ready.
Add in a handful of baby spinach and pulse a few more times to chop up into egg mixture. Pour egg mixture into muffin cups, filling about 3/4 of the way full. Top each egg cup with cheddar cheese and carefully place in the oven.: When you add the baby spinach , you should see tiny green flecks dispersed through the batter, which brightens the appearance and adds a vegetal note. Pouring requires a steady hand because filling to about three quarters leaves room for the mixture to rise slightly without spilling over. The sound of batter hitting the tin is soft and should not splash; if it does, you may be overfilling. Sprinkle the remaining cheddar cheese on top for a golden finish that gives a slight crispness once baked. A common misstep here is overfilling, which leads to overflow and uneven baking, so leave that headroom. Place the tin gently in the preheated oven so the cheese does not slide off or the sausage pieces shift.
Bake for 12-15 minutes, until the eggs are set. Let cool slightly before removing. Once cooled completely, you can store in the fridge for up to 7 days.: During baking, you will notice the tops transform from glossy to matte and the edges pull slightly away from the tin, which are reliable indicators of doneness. The smell in the kitchen will be a warm, savory mix of melted cheddar cheese and cooked turkey sausage links , and the visual cue is a lightly golden top with no jiggle in the center. Letting them rest briefly helps the steam redistribute, preventing soggy interiors, while full cooling makes removal cleaner and preserves texture. A common mistake is slicing or storing while still hot, which traps condensation and softens them; allow them to cool to room temperature before refrigerating. Stored in an airtight container, they remain ready and maintain texture for several days, but reheating gently is best to revive the creamy interior.