In a medium bowl add the following ingredients: cilantro, parsley, green onions, cubanelle pepper, mozzarella cheese, feta cheese, egg whites, salt, ground black pepper, sour cream and give it a good mix. Set aside.
Sprinkle some flour on the board and set one sheet on it. Use a rolling pin to make the dough a bit thinner and wider, by about 1 inch.
Add 2 tbsps of the cheese and herb mixture on the dough and fold it into a triangle. Seal the edges with a fork.
Repeat steps 2 and 3 for the rest of the sheets and mixture.
Brush the pastries with the 3 egg yolks you set aside.
Sprinkle with some sesame seeds.
In a preheated 400F oven, bake 20-25 minutes until golden brown.
