In a large bowl, stir together 1 1/3 cups granulated sugar and 2 1/2 Tablespoons all-purpose flour until combined.
Add 3/4 cup buttermilk, 1/2 cup (1 stick) salted butter, melted, 3 large eggs, 1 Tablespoon fresh squeezed lemon juice and 2 teaspoons vanilla extract and whisk until smooth.
Pour the mixture into 1 (9-inch) deep dish pie crust that is set on top of a sheet tray. This will help catch any spillage.
Bake for 55-70 minutes until golden brown on top. The pie will puff up and will still be slightly jiggly. If it appears to be browning too fast, you can cover it with foil.
Allow to cool for at least 3 hours at room temperature; serve or place in the fridge until ready to serve if you prefer it cold. Optional: Dust with powdered sugar or serve with a dollop of whipped cream.
Video
Notes
Please refer to my FAQ’s (Frequently Asked Questions) and ingredient list above for other substitutions or for the answers to the most common questions.