Buttermilk Pecan Pie

1 9" pie shell; unbaked
½ cup unsalted butter
2 cup granulated sugar
2 teaspoons vanilla
3 eggs
3 tablespoons all-purpose flour
¼ teaspoon sea salt
1 cup buttermilk
½ cup Pecan Pieces

Preheat oven to 300°. In a large mixing bowl cream butter and sugar until light and fluffy, adding ½ cup sugar at a time. Blend in vanilla. Add eggs, one at a time. Combine flour and salt; add small amount at a time. Add buttermilk. Sprinkle pecans in bottom of pie crust; pour custard mix over the pecans. Bake in a preheated oven for 1 hour 30 minutes.