Preheat oven to 375 degrees F. In a small bowl, blend Litehouse® Feta Cheese, Litehouse® Instantly Fresh Spring Onion, and egg. Cut pastry into 12 squares. Place a mounded Tbsp. of feta mixture in the center of each square. Moisten edges with water, and fold pastry over filling to form a triangle. Press edges together firmly with a fork to seal. Brush pastries with the egg yolk mixture. Bake for 20 minutes in the preheated oven, or until golden. Serve warm.