Preheat oven to 375 degrees F.
Roll the dough out on a lightly floured surface to a 12-inch circle. Carefully transfer the dough to a 10-inch fluted tart shell with removable bottom and ease the pastry into the bottom and sides of the shell. Press the dough into the shell and trim the top edges to form a clean edge. Using the tines of a fork, lightly dock the base of the shell. Place the shell into the oven and bake until lightly browned, 12 to 15 minutes. Remove from the oven, brush the baked shelled bottom with the egg white, and sprinkle with the chopped pecans
. Set aside until ready to use.
Rub the sweet potatoes with the vegetable oil and roast
in the oven for 45 to 60 minutes, until very tender. Remove and set aside to cool. Peel
the potatoes and pass the flesh through a fine mesh sieve
using a rubber spatula
. You should have about 1 1/2 cups smooth sweet potato puree.
In a medium mixing bowl, combine the sweet potato puree with the sugar, maple syrup
, cinnamon, nutmeg
and salt. Whisk
to combine. In a separate bowl, combine the heavy cream with the eggs
and whisk to combine. Add the cream and egg mixture to the sweet potato mixture and stir to blend. Pour the batter
into the prepared tart shell and place the tart on a sheet pan
. Bake until the center is set and the tart
is golden brown, about 30 to 35 minutes. Remove the tart from the oven and allow to cool for at least 20 minutes before serving.
To serve, slice the tart into 8 servings. Spoon 3 to 4 tablespoons of the anglaise onto each dessert plate, then top with a slice of the tart. Drizzle
each slice with some of the chocolate sauce and dust
with powdered sugar
. Serve immediately.