In a large bowl, whip the heavy cream with the powdered sugar.
On a plate, place 7 wafer cookies—6 around the edges, and one in the center. If desired, put a dab of the whipped cream mixture on the plate, beneath each cookie, to keep them stationary.
Put 1/2 cup of the whipped cream mixture over the cookies. Add the next layer of 7 cookies, then another 1/2 cup of the whipped cream mixture. Keep layering until the cookies are gone.
Refrigerate. When ready to serve, cut as you would a round layer cake.