This is another Christmas favorite at my house
1 9 inch Pie Crust
1/4 tsp cinnamon
1 cup plus 1 tablespoon sugar
4 tablespoons butter, melted and cooled
1 1/2 cups buttermilk
4 large egg yolks
1/4 cup all purpose flour
1 teaspoon vanilla extract
Preheat oven to 350 F. Set a rack in lower third of oven. Line a baking sheet with foil or use a disposable aluminum pan, set it on oven race.
In a small bown stir together cinnamon and 1 tablespoon sugar. In a large bowl whisk together melted butter, buttermilk, egg yolks, flour, vanilla and remaining sugar. Pour into pie shell and sprinkle with the cinnamon/sugar mixture.
Set pie on preheated baking sheet and bake for 2o minutes. Without opening oven turn oven down to 325 F and bake until pie is set, puffy and golden (about 20 more minutes). Let cool on wire rack, then serve warm or chill to serve cold.