Preheat the oven to 350 degrees F. Grease 9 muffin tins very well with oil or cooking spray. Set aside.
Add the oil to a skillet over medium heat. Add the diced onion and cook until tender, about 5 minutes. Remove from heat. Stir in the chopped spinach and set aside.
Add the eggs, cottage cheese, milk, salt, and pepper to a blender. Blend until smooth and fully combined.
Divide the onion and spinach mixture evenly between 9 greased muffin tins. Sprinkle the crumbled feta over the onion and spinach in each tin.
Pour the blended egg mixture evenly over the onion and feta. It is ok to fill to the top of the tin.
Sprinkle the grated Parmesan cheese over the top of each egg bite.
Bake for 15-20 minutes or until the eggs are fully set and no longer jiggly in the center.
Let cool for a few minutes before removing from the tins. Run a butter knife around the edges if needed to release them. Enjoy!
The nutrition facts provided are calculated using a third-party tool and are estimates only. Actual nutritional content may vary based on the ingredients and brands you use, as well as portion sizes. For accurate results, please consult a registered dietitian or nutritionist.