In a large nonstick skillet, heat oil till hot. Add bell peppers and onions and cook till peppers are very tender, about 10 minutes.
In a medium bowl, whisk together the eggs, egg whites, Italian seasoning, salt and pepper.
Stir the peas into the bell pepper mixture. Pour the egg mixture on top, reduce the heat to medium. Cover and cook till the eggs are just set in the center, about 7 minutes. Remove from heat, sprinkle parsley on top and serve frittata from the pan.
NOTE: You can substitute other frozen veggies for the peas. Just make sure to thaw before using to avoid a watery frittata.