9” deep dish pie crust (The recipe actually calls for a store bought crust. This sounds right up my alley!)
1 cup packed golden brown sugar
3 Tbls. all purpose flour
3 large eggs
1 egg yolk
1 tsp. vanilla
1 ½ cups buttermilk
3 Tbls. unsalted butter, melted and cooled
Position rack in center of oven and preheat to 400 degrees. Thaw pie crust 10 minutes. Bake crust until pale golden; about 12 minutes. Transfer to a rack and cool. Reduce oven temperature to 350.
Blend brown sugar and flour with mixer. Add eggs, yolk and vanilla. Beat until blended. Add buttermilk and melted butter and process just to blend. Pour mixture into cooled crust.
Bake pie until filling puffs and is almost set but center still moves slightly when pan is shaken; about 45 minutes.
Cool pie on rack to room temperature. Chill until cold, at least 2 hours and up to 1 day. Cut into wedges and serve.