Preheat oven to 375 degrees.
Combine flour, salt and sugar in a food processor until well blended, if adding nuts do so now and process until finely chopped.
Add the pieces of cold butter and mix in food processor until mixture resembles coarse meal.
Add egg yolk combined with cold water and vanilla to the mixture and process until the dough forms a ball inside the food processor bowl.
Remove dough and sandwich between parchment papers. Roll the dough into 10-inch circle and refrigerate until chilled.
Remove parchment and place dough in removable bottom tart pan. Be sure to push the dough up on the sides of the pan to form a thick crust barrier.
Using a fork, pierce dough with tines to prevent dough from bubbling up (called “docking”).
Spray parchment paper lightly with vegetable spray and place sprayed side against dough (this will prevent dough from sticking to parchment once parchment is removed).
Fill parchment lined pastry with pie weights or dried beans to weigh down dough for baking. (This technique is called “blind baking,” it’s purpose is to prevent the buttery dough from loosing its shape while baking in a very hot oven)
Place lined tart shell in the oven for 10 minutes. After 10 minutes, carefully remove bean-lined parchment from tart; place the tart shell back in the oven until the crust is lightly golden, about 5-8 more minutes.
As soon as the tart shell is removed, sprinkle 1/2 cup of chocolate chips on the crust and allow time for them to melt. Then, use a pastry brush to spread melted chocolate and coat the shell. Allow the shell to cool to room temperature and then refrigerate to firm up chocolate until ready to fill with cream filling. (Coating pastry with chocolate not only adds one of my favorite flavors to this dessert but it also creates a barrier between the flaky crust and the rich pastry keeping this tart delicious for several days – if it lasts that long!)