Make the chocolate crust: Position a rack in the lower third of the oven and preheat to 325 F. Remove the sides from a 10-by-3-inch springform pan. Trim a 10-inch cardboard cake circle so that it fits snugly within the curved lip of the bottom of the springform pan. Cover the circle with a piece of heavy-duty aluminum foil, leaving a 2-inch overhang all around the edges Carefully attach the side of the pan so you do not tear the foil . Wrap the foil overhang halfway up the outside of the pan. (Lining the bottom of the pan in this way will give the cheesecake an even flat base, making it easy to remove from the pan.) In a small bowl, stir together the cookie crumbs and melted butter, stirring until well combined. Press the mixture evenly over the bottom of the prepared pan. Refrigerate the crust while you prepare the ganache and filling. Make the ganache: Place the chocolate in a medium bowl. In a small saucepan set over medium heat, bring the cream to a gentle boil. Pour the hot cream over the chocolate and allow the mixture to stand for 30 seconds to melt the chocolate. Whisk until smooth. Measure out 2 cups of the ganache for the cake filling and set aside. Measure out 1 cup of the ganache for the chocolate truffles, cover and refrigerate until firm enough to pipe. Cover the remaining ganache and set aside at room temperature. Make the filling: Place the cornstarch in a small bowl. Gradually whisk in the cream and the vanilla, and whisk until smooth.