Preheat the oven to 350 degrees F (175 degrees C).
Roll out pie dough large enough to fit pie dish with just a bit of overhang. Transfer dough to pie dish and gently fit into dish. Trim excess dough hanging over the edge. Fold about 1/2 inch of the edge of the dough to the inside edge of the pie crust to reinforce it. Crimp the edge. Prick the bottom and sides of the crust with a fork about 10 times. Place a sheet of parchment paper gently into the crust and fill with pie weights or dried beans so pie crust doesn’t bubble up with you bake it.
Bake crust in the preheated oven for 15 minutes. Remove the dish from the oven; lift weights from pan with edges of parchment paper. Allow crust to cool completely.
Place butter in mixing bowl; add sugar. Stir together until completely combined using a spatula, 4 or 5 minutes. Add flour and salt. Mix together until combined. Stir in 3 eggs; mix until slightly blended. Then using a whisk, whisk together until mixture is fairly smooth and creamy.
Pour in vanilla extract. Add nutmeg, zest of lemon, lemon juice, and buttermilk. Whisk until thoroughly mixed, 2 or 3 minutes. Pour into the pie shell.
Bake in the preheated oven until golden brown and just set, 45 to 55 minutes. Pie should have a slight wiggle, but not a soupy jiggle. Cool to room temperature. Refrigerate until chilled, 1 to 2 hours.
