Preheat oven to 400 degrees.
In a medium sized bowl or mixer, mix together the sugar, flour, and nutmeg on the lowest speed.
Pour in butter and mix together.
Add the eggs and thoroughly mix in, one at a time.
Slowly pour in the buttermilk while mixing. Add in the lemon juice and zest, blending for 30 seconds. Scrape down the insides of the bowl for any unmixed batter. Blend for an additional 30 seconds.
Evenly pour the mixture into the unbaked pie shells.
Put the pies into the oven, and set a timer for 50 minutes. Once the timer is set, turn the oven down to 325 degrees.
Once baked, let cool to room temperature before refrigerating.