Coffee-Chocolate Ice Cream Cake with Nuts and Espresso Whipped Cream Frosting

1. Butter a 9-inch springform pan and line the bottom with a parchment paper circle.
2. Cover the bottom of the pan with the pound cake, using any extra pieces to line the sides of the pan if desired. Sprinkle 1/2 cup of the nuts on top. Scoop the chocolate ice cream onto the nut layer, packing it in tightly. Spread with an offset spatula to make a smooth top. Scoop the coffee ice cream over the chocolate ice cream, spreading with the offset spatula to make a smooth top. Cover with plastic wrap and freeze until firm, 2 to 2 1/2 hours.
3. Unmold the cake by running a knife around the edge of it, then unhinge the springform and remove. Invert the cake onto a sheet of plastic wrap and remove the bottom of the pan and the parchment. Place a plate on the bottom and invert once more.

For the espresso whipped cream frosting: 

1. Put the heavy cream, espresso, confectioners' sugar and vanilla in a large bowl and whip with an electric mixer until soft peaks form. (This makes enough frosting to cover the top and sides of the cake with additional to pipe decorations if desired.)
2. Frost the top and sides of the cake with the whipped cream frosting, sprinkle with the remaining 1/4 cup nuts and drizzle with the chocolate sauce. If the cake begins to get too soft, put it back into the freezer for a few minutes.
3. Freeze another 1 1/2 to 2 hours or overnight. Before serving, let the cake sit at room temperature for about 20 minutes.