Preheat the oven to 375 degrees F. Thoroughly spray standard muffin pans with nonstick cooking spray.
Place the eggs, cream cheese, yogurt, salt, garlic powder, and cayenne in the food processor. Pulse until smooth. Press the spinach firmly in a colander to remove all excess moisture. Then stir the spinach and shredded cheddar into the egg mixture.
Use a 1/2 cup scoop to portion the egg mixture evenly into the muffin tins. Bake for 15-20 minutes, until the centers are set and puffy. Run a butter knife to around the edges of each muffins to loosen from the pan.