Preheat oven to 375°F. On a well-floured surface, roll out prepared pie crust dough into a 12-inch circle. Transfer to a 9” pie plate, tuck edges under and crimp as desired. Freeze for 20 minutes.
Prick the bottom of the crust 8-10 times with a fork. Gently line the pie crust with foil and fill with pie weights. Bake for 10 minutes, until the edges of the crust are dry.
Remove from oven and carefully remove pie weights. Return to oven and continue baking another 5 minutes, until the bottom of the crust is dry and light brown. Remove from oven and let cool.
Pie Filling
In a large bowl, whisk together sugar and melted butter. Whisk in eggs and egg yolk, then flour. Add the buttermilk, lemon zest, lemon juice, and vanilla extract.
Pour filling into cooled pie shell. Bake 45-50 minutes, or until lightly golden brown with the edges and center set.
Let pie cool completely before serving, about 2 hours. Garnish with whipped cream and enjoy!