Heat small skillet, lightly coated with spray, over medium-high heat.
Add egg whites; do not stir. As eggs set, lift edges, letting uncooked portion flow underneath; cook for 1 to 2 minutes, or until set.
Spread marinara sauce evenly on top of egg whites. Then top with cheese, kale (if desired), and mushrooms (if desired); cook, covered, for 1 to 2 minutes, or until cheese melts.
Cut into four slices; serve immediately
Tips:
The Nutrition Facts box below provides estimated nutritional information for this recipe.