For the Tart Dough: This recipe works best with very cold butter. Cut the butter into 1/2-inch cubes. Since butter softens rapidly with handling, return the cubes to the refrigerator for at least 10 minutes while you set up the food processor and gather the dry ingredients. Place the flour, sugar, and kosher salt, in the bowl of a food processor fitted with the steel blade. Pulse on/off a few times to combine. Add the butter, tossing quickly with a spatula to coat each cube with flour. This prevents the butter cubes from adhering together and helps them to break apart and combine more evenly with the flour. Pulse on and off 15 times until the butter particles are the size of small peas. With the motor running, add the ice water all at once through the feed tube. Process for about 10 seconds, stopping the machine before the dough becomes a solid mass. Turn the contents of the bowl onto a sheet of aluminum foil, pressing any loose particles into the mass of dough. Roughly form the dough into a 7-inch disk. Cover the dough completely with aluminum foil and refrigerate for at least 1 hour or until ready to use. The dough may be refrigerated up to 2 days or frozen for up to 2 weeks. Let dough rest in refrigerator until needed.
For the Tart: Divide the dough into 4 equal portions. Roll out each portion of dough on a floured surface into 9-inch free form circles, about 3/8-inch thick, and transfer to baking sheets. Cover and chill the dough while you prepare the filling. Mix the ricotta, egg yolks, tangerine peel, sugar and cinnamon in a bowl. Stir with a rubber spatula until well combined. Scatter the chopped dates over the surface of the tart shell leaving a 1 1/2-inch border around the outside edge. Spoon the filling over the dates and raise the dough border to enclose the sides of the tart. Press down on the dough where if forms pleats to secure. Bake the tart for 15 to 18 minutes, in preheated 450 degrees, until the crust is golden and the filling is just set. Cool on a rack for 10 minutes, dust with confectioners' sugar and serve warm.
Recipe courtesy of Johanne Killeen, George Germon, "Al Forno Cookbook"