- Preheat the oven to 350°F. Lightly oil or coat a 6-cup muffin pan with nonstick cooking spray and set aside.
- Crack the eggs into a large bowl. Whisk until well combined. Stir in the kale, green onion, Cheddar cheese, and oregano until well combined.
- Use a ⅓ measuring cup to divide the mixture evenly into the prepared muffin cups. Top evenly with the Parmesan cheese.
- Bake until the eggs are set, about 18 minutes. Cool slightly, remove, and serve.