Place a large piece of parchment on a heat-resistant work surface or baking sheet.
Combine nuts and maple syrup in a heavy medium-sized skillet over medium-high heat and bring to a boil, tossing to coat.
Cook until syrup is dark amber and almost cooked away and thickly coats nuts, tossing often, 3 to 3-1/2 minutes.
Scrape nuts onto the parchment paper.
Working quickly separate the nuts. Sprinkle with coarse salt.
Cool until coating is crisp and hard, about 1 hour.
For the caramel sauce:
Melt butter in a medium-sized saucepan over medium heat.
Add sugar and whisk until sugar melts and the mixture is thick and boiling - about 2 to 3 minutes.
Gradually whisk in cream and bring sauce to boil, whisking often.
Boil until sauce thickens enough to coat a spoon and is reduced to 1 cup, whisking often - about 2 to 3 minutes.
Remove from heat.
Whisk in coarse salt and extract.
For cake:
Preheat oven to 350 degrees F.
Spray two 9-inch cake pans with non-stick cooking spray.
In a food processor, combine the all-purpose flour, Chinese five-spice powder, baking soda, and kosher salt. Process until combined. Add in the crystalized ginger and blend until ginger is finely ground - about 1 minute.
Using a stand mixer, beat maple sugar and butter until light and fluffy.
Add the eggs, one at a time, and fully combine. Don't worry if the batter looks slightly curdled, this is normal.
In a small bowl add hot water and molasses in a small bowl.
Add the dry ingredients into the butter mixture in 4 additions alternately with the molasses mixture.
Divide the batter between the prepared pans and baked until a tester inserted into the center comes out clean, about 30 minutes.
For frosting:
Combine the creme fraiche, heavy cream, maple sugar, powdered sugar, and Chinese five-spice powder to a stand mixture and beat until very thick and stiff.
For assembly:
Cut around pan sides to loosen cake layers and turn out onto racks.
Place 1 cake layer on a platter and spread with 1-1/3 cups frosting.
Drizzle with 3 tablespoons of caramel sauce and top with a second cake layer.
Spread the remaining frosting smoothly over the top and sides of the cake.
Drizzle the top of the cake with 3 tablespoons of caramel sauce. Cover the cake and chill for at least an hour. Cut pecans into pieces or leave them whole.
Press pecans into the frosting on the cake.
Store for at least an hour in the refrigerator before serving.
Leftovers should be stored in the refrigerator for up to 4 hours.