Preheat oven to 400 degrees.
Defrost puff pastry dough and cut each sheet into 12 squares.
Spray mini muffin tin with oil.
Press puff pastry dough squares into each mini muffin tin.
Melt butter in saucepan.
Add garlic.
Sautee one minute.
Add spinach, nutmeg and pepper.
Sautee 3-5 minutes or until heated through.
Turn heat to low and add cream cheese. Stir until melted and well combined.
Stir in mayonnaise, sour cream, parmesan and mozzarella.
Continue stirring until well combined and cheeses melt.
Divide dip between 24 tart shells.
Cover loosely with foil and bake 8 minutes.
Remove foil and brush edges of tarts with egg.
Bake for additional 8-10 minutes.
Enjoy!