01 - Preheat oven to 350°F (175°C). Lightly grease a standard 6-cup muffin tin with cooking spray or olive oil.
02 - In a mixing bowl, whisk eggs, ranch dressing, garlic powder, salt, and black pepper until well blended.
03 - Fold in diced chicken, avocado, scallions, cherry tomatoes, spinach, and shredded cheddar cheese until evenly distributed.
04 - Divide mixture evenly into each muffin cup, filling each about three-quarters full.
05 - Place tin in oven and bake for 22–25 minutes, or until egg cups are puffed and set in the center.
06 - Allow to cool for several minutes, then carefully remove egg cups from tin. Serve warm.