Preheat your oven to 375°F and lightly coat a muffin tin with nonstick spray.

Divide the spinach evenly across the muffin cups, then add the diced cherry tomatoes on top.

Pour in the egg whites, filling each cup nearly to the top, and season with salt and pepper. Sprinkle a little feta cheese on each one.

Bake for 17-20 minutes, or until the egg whites are firm and slightly browned on the edges. Let them cool for a few minutes.

Use a butter knife to carefully loosen each egg bite around the edges and gently lift them from the muffin tin.

Serve them warm and enjoy!