Pulse flour, butter, and icing sugar in a food processor to form fine breadcrumbs.
Add egg yolks and milk, pulsing until the dough comes together.
Form dough into a ball, wrap, freeze for 10 minutes, then refrigerate for 20 minutes.
Boil sweet potatoes in salted water for 10 minutes or until tender.
Roll pastry to 0.5cm thickness and line a greased 28cm tin.
Press chopped pecans into the pastry, prick with a fork, and chill for 20 minutes.
Preheat oven to 170°C.
Blind bake with parchment and beans for 10 minutes, then bake alone for 15 minutes.
Mash sweet potatoes and mix with sugar, eggs, spices, condensed milk, vanilla, and melted butter.
Pour filling into the case, top with pecan halves and cinnamon.
Bake for 25 minutes until the filling is set.
Cool for 10 minutes, remove from tin, and chill in the fridge once at room temperature.