In a medium size mixing bowl, add whipping cream and turn beater on to medium-low (if you are using a hand mixer, don't start to whip - add all ingredients first since you'll need both hands)

Add icing sugar and vanilla, increase speed to high and whip for about 4-5 minutes, until you have stiff peaks.

Spread 1/4 cup whipped cream onto the base of your 9" round pan (an offset spatula makes this really easy)

Press an even layer of cookies on top of the whipped cream. Break cookies into pieces to fill big spaces, but don't worry too much about small spaces

Spread 1 1/4 cups whipped cream on top of this first layer of cookies

Add a layer of cookies again, filling in spaces where necessary

Repeat until you have three layers of cookies

Finish with a thick layer of whipped cream (about 1 cup) on top

Cover with a foil or plastic wrap and leave in fridge for a minimum of 10 hours

Before serving, top with crushed cookies, sprinkle cocoa powder or shave chocolate over top layer