Preheat oven to 350 degrees F. Coat a muffin pan with cooking spray.
Crack the eggs into a medium bowl. Add the water and whisk until mixture is fluffy. Divide between the muffin cups, filling each approximately 2/3 full.
Add the extras to the cups, as desired, making sure the contents don’t spill over the edges. Bake in the preheated oven for 30 minutes, or until the eggs are cooked through.