Crack the eggs into a large bowl. Add the onion powder, garlic powder, salt, pepper, and cayenne. Whisk well to combine.
Step 2
Roughly chop the onions. Crumble the feta and shred the cheddar cheese. Peel and finely chop the avocado. Add the onions, feta, cheddar, and avocado to a bowl. Toss to combine.
Step 3
Preheat the oven to 160°C (320°F). Grease a 6-cup muffin tin with butter. Divide the cheese mixture evenly between the prepared muffin cups.
Step 4
Pour in the egg mixture. Bake for 20 minutes. When done, remove from the oven and cool for 10 minutes.
Step 5
Serve the muffins immediately. They pair perfectly with tomatoes and fresh arugula. Optionally, serve with sour cream.