Preheat oven to 300 degrees. For the crust whip together 4 ounces butter, egg, salt, 1/3 cup sugar and vanilla together. Add the flour and incorporate completely. Form into a ball and turn out onto a floured surface. Roll the dough out to 14 inches and 3/4-inch thick. Blind bake the shell for 10 minutes in a tart pan.
For the filling. Melt the chocolate and 1 1/3 cup cream together. Pour into the baked shell and chill for 1 hour. Top the ganache with the roasted pecan pieces and chill for another hour. For the caramel: Combine the karo, 3 tablespoons butter, 3/4 cup sugar and 1/2 cup heavy cream. Bring the mixture to a boil and cook until the caramel reaches the thread stage, (210 degrees). Allow the caramel to cool before pouring over the top of the ganache. Place a piece of the pie in the center of the plate. Garnish with chocolate sauce, whipped cream, mint and powdered sugar.