Beat 1 cup heavy cream, 3/4 cup mascarpone, the confectioners' sugar and vanilla in a bowl with a mixer on low speed until combined. Increase the speed to medium and beat until stiff peaks form, 1 to 2 minutes.
Combine the remaining 3/4 cup each heavy cream and mascarpone with the chocolate-hazelnut spread in a separate bowl. Beat with the mixer on low speed until combined, then increase the speed to medium and beat until stiff peaks form, 1 to 2 minutes.
Line the bottom of an 8-inch springform pan with 4 graham crackers in a single layer, breaking them into pieces to fit and fill any big gaps. Spread half of the vanilla whipped cream over the graham crackers, then top with another layer of graham crackers. Spread half of the chocolate-hazelnut whipped cream on top. Repeat with another layer of graham crackers, the remaining vanilla whipped cream, then more graham crackers and the remaining chocolate-hazelnut whipped cream. Cover the pan with plastic wrap and refrigerate at least 6 hours or overnight.
Uncover the cake and run a thin knife around the edge to loosen. Remove the springform ring; smooth the sides of the cake using an offset spatula. Put the remaining 4 graham crackers in a large resealable bag; crush into fine crumbs using the bottom of a skillet. Press the crumbs around the side of the cake.
Photograph by Kana Okada
Courtesy of Food Network Magazine