saute garlic, chicken and butter in sauce pan, stirring occasionally, until garlic is lightly browned and butter is melted(7 minutes is usually good). Then add chicken, spinach, and cheeses until mixed well, and cheese starts to melt.
mix eggs and milk into a bowl until blended, then add everything from the pan into the bowl, making sure to mix the eggs in, well.
spread the pie crusts evenly along the bottom of a glass casserole dish, sides folded up a little along the sides.
spoon mixture evenly onto pie crusts and bake for 30-40 minutes on bottom rack, or until cheese is browning lightly and crust has risen (ovens vary, so keep an eye on it!)