Prepare the Oven and Pie Shell - Preheat your oven to 325°F (165°C). While the oven is heating, place your pie shell in the refrigerator to chill. This keeps the crust flaky and prevents it from becoming soggy when the wet filling is added.

Cream the Butter and Sugar - In a large mixing bowl, use a hand mixer on medium-high speed to cream the butter and sugar together until the mixture becomes light and fluffy, about 2 to 3 minutes. This process incorporates air into the batter, which helps create a lighter texture in the finished pie.

Add Dry Ingredients - Add the flour and salt to the butter-sugar mixture and beat for 15 to 30 seconds until fully incorporated. The flour helps to stabilize the filling while baking.

Incorporate the Eggs - Add the eggs one at a time, beating well after each addition. This method ensures the eggs are fully incorporated without overbeating, which could cause the filling to become too airy.

Add Liquid Ingredients - Pour in the buttermilk and vanilla extract, then continue beating until everything is well combined. The mixture may look slightly curdled, but this is normal due to the acidity of the buttermilk.

Fill and Bake the Pie - Place your chilled pie shell on a baking sheet, then carefully pour the buttermilk filling into the shell. The baking sheet makes it easier to transfer the pie to and from the oven and catches any potential overflow during baking.

Bake Until Set - Bake for 60 minutes or until a knife inserted in the center comes out clean. The pie should have a slight jiggle in the center but be mostly set when done.

Cool Before Serving - Remove the pie from the oven and allow it to cool completely on a wire rack before serving. This cooling period allows the filling to fully set.