Roughly break each biscuit into quarters and set aside.
Add the boiling water to the hot chocolate and cocoa in a double boiler (bain Marie), stirring until the mixture is smooth.
Add butter, sweetened condensed milk. sugar. and vanilla and stir till smooth.
Than add and the beaten eggs, keep stirring till it turns into a thick custard.
Transfer the thick custard to a large mixing bowl, add quartered biscuits and any other additions wanted and mix until its all coated with the custard.
Lastly transfer the mixture to the prepared tin .
Press down firmly so there are no air pockets in the mixture. Remember to bang the tin on the bench a couple of times so that its set. and fold the paper extensions on the top and press down to even the surface. Let it cool to the touch.
Place into the refrigerator to chill for at least 4 hours or preferably overnight.