In a large bowl combine the flour, sugar, and salt. Add the cold diced butter and cut with a fork or pastry blender. Mix until the butter breaks down and the mixture gets coarse and crumbly, about the size of peas. In a small bowl, whisk together the egg yolk (saving the white in a separate bowl) with the two tablespoons of ice water. Make a well in the center of the dry ingredients and pour the egg yolk-ice water mixture. Stir with a rubber spatula and mix until the dough comes together and forms a ball. If it is too dry add more water, a tablespoon at a time until it forms a ball. You can knead it with your hands to bring it together faster. Shape the dough into a disc and wrap with plastic. Place in the fridge and allow to chill for at least 30 minutes, an hour would be best.

Preheat oven to 350°F. Lightly flour a work surface and roll out the chilled dough into a large circle about ¼ of an inch thick. Carefully place the rolled dough into a 9-inch tart pan with a removable bottom. Make sure to press the dough evenly up the sides, cutting the excess dough hanging over. Cover with aluminum foil and fill with dry beans or pie weights. Place on a sturdy baking sheet and bake for 30 minutes. Remove the tart from the oven and discard the foil. Whisk the reserved egg white with a splash of water. Brush the warm tart, evenly, with the egg white. Return to the oven and bake for another 8 minutes or until golden brown. Allow to cool on a rack.

To make filling, add the chocolate chips into a large bowl. Pour the heated cream and milk over the chocolate and let it stand, untouched, for a few minutes. Then add the sugar, espresso powder, cinnamon, coffee liqueur, vanilla and salt. Whisk until completely smooth and glossy. In a small bowl, whisk the eggs and a few tablespoons of the warm chocolate mixture (this will temper the eggs making sure they don't curdle once you add them). Slowly stream in the eggs, while whisking vigorously, into the chocolate mixture. Continue to whisk until the filling is smooth and glossy. Pour the filling into the cooled crust (it might appear not to fit but it will). Return the tart to the oven and bake for 20 to 25 minutes or until the filling has set and doesn't jiggle when the tart is lightly shaken. Place on a cooling rack and allow to cool completely before serving. Cut and serve or you can cover the tart with plastic and store in the fridge until ready to eat. Will keep for up to 5 days in the refrigerator. Enjoy!