Thaw the puff pastry and roll to flatten. Make sure to roll it on a floured surface or it will stick.
Brush the beaten egg over the entire top of the pastry.
Combine cheeses and garlic powder and sprinkle evenly over the pastry.
Spread spinach evenly over all
Roll up lengthwise and cut into slices (about 1/4 in).
Place on cookie sheet and brush any remaining egg over tops of slices. (It is easier to slice if you refrigerate the dough for a few minutes after you have put the roll together)
Bake at 425 for about 15 minutes or until golden brown.
Can serve hot or room temperature. They taste best if eaten the same day. You can serve them a day or two later but they aren't as crisp and puffy (if you pop them in the oven for a minute or two they will crisp up but won't be quite as fabulous as if you served them shortly after baking.