Preheat the oven to 350 degrees Fahrenheit. To prepare the crust, mix together all of the dry ingredients in a large bowl. Cut the butter into pea-sized pieces over the bowl, or pulse together using a food processor. Add the ice water, a tablespoon at a time, mixing with a wooden spoon rather than your hand to help keep the dough cool, until fairly well mixed (it's okay if there's still some small blobs of butter).

Grab a handful of the dry crumbly dough mixture and squeeze. If it holds together you don't need to add anymore water. Roll the dough out until it is about 1 centimeter thick, then place it over a well-greased and lightly floured 8-inch pie dish (mine measures about 2 inches deep).

Trim the edges and use the remaining dough to create a decorative border by cutting out shapes, (or just place the remaining dough in a freezer-safe plastic bag and freeze for when you want to make another pie). Place the crust in the refrigerator.

To prepare the filling, beat the eggs, granulated sugar, brown sugar, corn syrup, creme fraiche, cocoa powder, corn meal and salt until smooth. Add the butter, vanilla, and hazelnut extracts and mix until incorporated. Stir in the hazelnuts.

Pour the filling into the pie shell. Bake for 50 minutes to 1 hour or until the filling is set on top and the pastry is golden brown. Allow to cool for 1 hour before slicing and serving.