To make the crust. put the flour, confectioners’ sugar, and butter or margarine in the bowl of a food processor fitted with a metal blade. Process for 10 seconds, or until the mixture resembles sand. Add the egg yolk, cold water, and the vanilla and process until the dough barely comes together. Gather the pieces of dough and place on a large piece of plastic wrap, cover and flatten. Chill in the freezer for 2 hours or overnight.
Preheat the oven to 350ºF. Place the hazelnuts on one side of a jelly roll pan and the remaining nuts spread out on the other side. Toast the nuts for 20 minutes, stirring twice, keeping the hazelnuts separated. Let cool until you can handle the hazelnuts. Remove the hazelnuts to another bowl and grab handfuls and rub between your hands to remove the skin. Return the peeled hazelnuts to the other nuts. Use a large knife to roughly chop the nuts so that almost every piece is cut at least in half; some pieces can be smaller. Set aside. May be made one day in advance and nuts stored in a container at room temperature.
Remove the dough from the freezer and let sit at room temperature just until you can press it gently. Preheat the oven to 350°F. Place an 8-inch tart pan with or without a removable bottom on a cookie sheet. Place a piece of plastic wrap or parchment larger than the tart pan on the counter and sprinkle generously with flour. Place the dough on top. Sprinkle with a little more flour. Cover with a piece of parchment and roll on top of the parchment to roll out the dough until it is at least 1 inch larger than the tart ring. You will want to peel back the parchment and sprinkle some more flour on the dough 3 to 5 times while you are rolling.
Remove the top parchment cover. Place your hand under the plastic or parchment, lift the dough and turn over into the tart pan. Use your fingers to gently press the dough into the corners. Peel off the plastic or parchment and make sure the dough is pressed into the corners and patch any holes. Use a rolling pin to roll over the top to trim off the excess dough.
Freeze for 10 minutes. Line dough with foil and fill with beans or pie weights. Bake for 20 minutes. Lift up the edges of the foil to remove foil and weights and bake the shell for another 8 -10 minutes more, until the crust feels dry to the touch. Remove from oven and leave the oven on.
To make the filling, put the sugar and water in a heavy saucepan and heat over low heat, stirring to dissolve the sugar. Turn the heat up to medium-high and let boil until the mixture turns amber, stirring once or twice. This takes about 8 minutes so be patient.
Turn the heat to low, add the whipping cream, and stir until the caramel is smooth. Whisk in the butter or margarine, honey, vanilla and almond extract and cook for 2 minutes on medium heat. Add the toasted nuts and use a silicone spatula to mix well. Remove from heat and turn into a bowl. Let cool for 10 minutes, stirring occasionally. Place the nut mixture and any caramel in the saucepan into the tart shell and spread evenly. Bake for 20 minutes.
Let cool for 1/2 hour. Put the tablespoon of honey and teaspoon water into a small bowl and heat in the microwave for 15 seconds and stir. Use a pastry brush to brush over the nuts. Serve at room temperature. Store for 4 days covered at room temperature.
