Unfold puff pastry; cut each sheet into 12 sections. Place in greased mini muffin cups, pressing gently onto bottoms and up sides, allowing corners to point up.
In a large bowl, stir together spinach, cream cheese, mozzarella, feta, 1 egg, garlic, pepper and salt.
Spoon 1 TBS into each cup. Bring pastry corners together and pinch to seal.
In a small bowl, beat remaining egg. Brush over pastry edges. Bake until puffed and golden brown, about 20 mins.