Tart Shell: In a large bowl, stir the flour, cinnamon and sugar together. With the flat beater attachment of an electric mixer, pastry blender or your fingertips, work the butter into the flour mixture until it resembles coarse meal. Sprinkle in 3 or 4 tablespoons of the eggy water and mix it in until the dough comes together in a ball. On a lightly floured surface, take walnut-sized pieces of dough and, with the heel of your hand, smear them away from you into 6-inch streaks. Pat the dough into a disk, wrap in plastic and refrigerate for 2 hours or overnight.
Set a rack in the middle of the oven and preheat to 400 degrees F. Lightly coat a 9 1/2-inch tart pan with a removable bottom with nonstick vegetable spray. On a lightly floured surface, roll the dough into an 11 1/2-inch circle. Fit the dough into the pan. Trim the dough to a 1-inch overhang and double the dough over itself to reinforce the sides. Freeze for 30 minutes. Line the tart shell with aluminum foil and weight down with dried beans or pie weights. Bake for 15 minutes. Remove the foil and bake for 10 minutes longer or until lightly browned.
Lower oven temperature to 350 degrees F. In a medium bowl, work the butter into the flour, sugar and cinnamon to make the crumb topping. You may start with an electric mixer but finish by rubbing and pinching it with your fingers until it looks mealy and lumpy. In another medium bowl, mix together the molasses, corn syrup, eggs, and vanilla. Stir the baking soda into the boiling water, then mix it into the rest of the filling. Pour it into the shell, filling up to 1/4-inch from the top of the crust. Sprinkle on the crumb topping, taking care not to overfill the shell. Bake for 30 minutes until set on a rack in the middle of the oven. Mix the confectioners' sugar, the ground cinnamon and the arbol chile. Let cool and sprinkle with the sugar/cinnamon/chile mixture. Serve with plenty of whipped cream.