Preheat the Oven: Begin by preheating your oven to 350°F (175°C).

Prepare the Pie Crust: Place the unbaked pie crust in a 9-inch pie dish. You can crimp the edges for a decorative look if desired. Set aside.

Mix Dry Ingredients: In a large mixing bowl, combine the granulated sugar and flour. Mix well.

Add Wet Ingredients: Beat in the melted butter until the mixture is smooth. Then, one at a time, beat in the eggs, ensuring each egg is fully incorporated before adding the next. Stir in the vanilla extract.

Add Buttermilk: Slowly pour in the buttermilk while stirring, and mix until all ingredients are well combined.

Fill the Pie Crust: Pour the buttermilk mixture into the prepared pie crust.

Bake: Place the pie in the preheated oven and bake for 45-50 minutes, or until the center is set and the top is lightly browned. You can check the doneness by inserting a knife into the center of the pie; if it comes out clean, the pie is done.

Cool and Serve: Remove the pie from the oven and let it cool on a wire rack for about 1-2 hours. Once cooled, you can refrigerate it for an additional 1-2 hours for best results. Slice and serve!