Make base by melting the butter, adding the sugar, and crushing and adding the chocolate biscuits. Mix well together and press into base of a buttered 8" or 9" spring clip tin.
Dissolve gelatine in water and leave to cool.
Beat together cream cheese, sugar, yolks of eggs, and essence to taste.
Whip whites until stiff and cream until thick.
Beat cooled gelatine into cheese mixture, followed by cream and then whites folded in. Chop mints and fold into mixture, then turn into the tin and leave to set.
Whip cream for topping until thick and whites are stiff, and fold the two together. Use this cream to decorate the top of the cheesecake with the reserved mints.