A custardy navy bean puree is generously spiced with cinnamon for the filling of this fall-friendly pie. Martha made this recipe on episode 703 of Martha Bakes.
Rinse beans and transfer to a saucepan. Add 3 cups water and bring to a boil. Reduce to low, cover, and cook beans slowly until tender, 1 1/2 to 2 hours. Measure 1 cup beans and set aside, reserving remaining beans for another use.
On a lightly floured surface, roll out pate brisee to a 13-inch round about 1/8-inch thick. Fit dough into a 9-inch pie dish and press into bottom edges and up the sides. Trim edge, leaving a 1-inch overhang; fold edge under and crimp as desired. Freeze 15 minutes.
Preheat the oven to 375 degrees with the rack located in the lower third. Line crust with parchment paper, gently pressing the parchment into the edges of the crust; weigh down parchment with pie weights or dried beans.
Bake until the edges of the crust begin to turn golden, about 30 minutes. Carefully remove pie weights and parchment paper. Continue to bake until crust is golden brown in color, about 20 minutes more. Transfer the crust to a wire rack to cool slightly.
Reduce oven temperature to 350 degrees. In a blender, combine beans, evaporated milk, 2 tablespoons flour, sugar, butter, cinnamon, eggs, and vanilla. Blend until mixture is smooth.
Strain bean mixture through a sieve into a glass measuring cup. Pour filling into cooled crust and bake until golden filling is just set, 50 to 60 minutes. Let cool completely on a wire rack before serving with whipped cream, if desired.