Heat broiler in oven to high.
Whip together egg whites, cream, mascarpone, cream cheese, salt and pepper until most cream cheese and mascarpone is broken up. Small pieces are ok.
Heat an oven safe, non-stick skillet to medium, add butter, melt and turn to high. Coat pan with butter well.
Pour egg mixture into pan and cook half way using a spatula to stir eggs slightly.
Add mozzarella evenly over top of omelet and place in oven under broiler for about 1 minute to melt cheese and cook omelet through.
Top with grape tomatoes, basil leaves and fold over to enjoy!