YIELD: One 23 cm pie Preheat the oven to 350. MAKE THE CRUST: In a medium bowl, blend the graham cracker crumbs, butter and sugar. Stir in the milk chocolate. Press the crust mixture into the bottom and up the sides of a 23 cm pie plate. Refrigerate until ready to use. PREPARE THE FILLING: In a heavy medium saucepan, dissolve the sugar in the water over low heat, stirring constantly. Bring to a boil over medium-high heat, then let boil without stirring until the syrup turns a light amber. While the syrup is boiling, brush down the sides of the pan from time to time with a wet pastry brush to prevent crystals from forming. Remove the pan from the heat and stir in the hot cream (be careful, it will bubble rapidly). Continue stirring, over heat if necessary, until all of the caramel is dissolved into the cream. In a medium bowl, lightly beat the egg yolks. Whisk about half c. of the hot caramel cream into the eggs to warm them. Transfer the warmed eggs to the caramel cream in the saucepan. Stir in the chopped semisweet chocolate and the vanilla, stirring until melted and smooth. Pour the filling mixture into the pie crust. Sprinkle the pecans and chocolate chips on top. Bake for about 35 min., or until the center is just set. Transfer to a wire rack to cool completely, then refrigerate until firm, about 4 hrs