Preheat oven to 350℉. Prepare 10 baking cups by either spraying or brushing them very well with oil or lining them with silicone liners.
Squeeze out all the excess moisture in the defrosted spinach, using a clean kitchen towel or a few layers of paper towel or by putting it in a strainer and pushing down on it with a spoon.
In a large bowl, mix the eggs, cottage cheese salt, garlic powder, and pepper.
Use an immersion blender to blend the mixture until smooth. About 15 seconds. If you do not have an immersion blender, you can do this in a regular blender and then pour the blended egg mixture into a large bowl.
Add the the drained spinach and feta to the bowl with the blended egg mixture. Use a whisk to mix the spinach and cheese into the eggs until everything is evenly distributed into the mixture.
Portion the veggie + egg mixture evenly between the 10 prepared muffin cups. filling each cup until they are almost full. Sprinkle with extra feta cheese, if desired
Place the muffin tin in the oven and bake until the egg bites are set, no longer jiggles, and is slightly golden on top. About 20-22 minutes. Let the egg bites cool for 10 minutes to setup then enjoy!