Line a 9*9 square pan with cling film and let the film hang to the edges of the pan so that you can later pull out the cake easily.Now, pour whipping cream in a bowl and beat with an electric beater/mixer until stiff peaks.If you want, you can dip the oroes in milk and then line them, but I did not dip them because the whipped cream can moisten the cookies as well.In the lined pan, arrange oreos in a row of four. 16 oreos fit in a 9*9 square pan.Using a spatula, slather whipped cream over the oreo layer and smoothen the top.Again arrange a second layer of oreos on top of the cream. 16 again.Finally the last layer of whipped cream from top, smoothen it out and garnish with crushed oreos.Refrigerate overnight or for 5 hours atleast.When chilled completely, take out of the refrigerator, pull the cake out using the cling film ends and place on a plate.Slice and serve.