buttermilk pie recipe

**Ingredients:** - 1 1/2 cups granulated sugar - 3 tablespoons all-purpose flour - 1/2 teaspoon salt - 1/2 cup unsalted butter, melted and cooled - 3 large eggs, room temperature - 1 cup buttermilk - 1 tablespoon lemon juice - 1 teaspoon vanilla extract - 1 unbaked 9-inch pie crust