Preheat your oven to 350 degrees Fahrenheit. Spray a 12 cup muffin tin well with nonstick cooking spray. This step is important to prevent sticking.
In a blender, combine the liquid egg whites, whole eggs, and cottage cheese. Blend on high for about 20 seconds until the mixture is smooth and frothy. The cottage cheese disappears into the eggs, making them extra creamy.
Add the salt, pepper, and garlic powder. Pulse a few times to mix in the seasonings.
Stir in the spinach, bell pepper, and green onion. Do not blend these.
Use a spoon or spatula to fold them into the egg mixture. You want the pieces to stay visible.
Sprinkle the shredded cheddar cheese evenly into the bottom of each muffin cup. This helps create a little cheesy layer at the bottom.
Pour the egg mixture into each cup, filling them about three quarters full. The bites will puff up a little in the oven.
Bake for 18 to 22 minutes. The bites are done when the centers are set and a toothpick inserted in the middle comes out clean. Do not overbake or they will become rubbery.
Let them cool in the pan for 5 minutes. Run a knife around the edges to loosen them, then transfer to a wire rack to cool completely.