Chill the butter in the freezer for 15 minutes.
Pulse the raw pecans in a food processor until finely ground, 6 to 7 pulses. Add the flour and salt, and pulse an additional 4 to 5 times. Add the chilled butter and pulse until the texture looks mealy, 6 to 7 pulses. Add the water and 2 tablespoons of rye, and pulse until the mixture holds together when squeezed in the hand, 5 to 6 more pulses. Transfer the dough to a 1 gallon zip-top bag, squeeze together with your hands until it forms a ball, then press into a rounded disk and refrigerate for 30 minutes.
Heat oven to 350ºF.
Whisk the eggs, sugar, golden syrup, butter, rye whiskey, the bitters, vanilla, and salt together in a medium mixing bowl until combined and set aside.
Remove the dough from the refrigerator. Cut along two sides of the zip-top bag, open the bag to expose the dough, and sprinkle both sides lightly with flour. Cover with the bag and roll out with a rolling pin to an 11-inch circle. Open the bag and lift the dough into a 9 1/2 x 2-inch tart pan. Gently press the dough into the pan, working it halfway up the side.
Chop 6 ounces of the spiced pecans, sprinkle them evenly into the crust, then pour on the filling. Bake in the middle of the oven for 20 minutes.
Remove the pie from the oven and close the door. Place the remaining 2 ounces of whole spiced pecans in a border around the edge of the filling then return to the oven for 15 more minutes or the internal temperature reaches 200 F and no longer jiggles loosely in the center.
Cool the pie on a wire rack for an hour before cutting and serving at room temp, possibly topped with our Slightly Sweet Whipped Cream.
To store, tightly wrap the remaining pie with plastic wrap and place in the refrigerator for up to 4 days. (Honestly, I haven't been able to make one last more than 9 hours, but feel free to beat me on that.)