Over hot but not boiling water melt the chocolate with the glucose and rum. Taking care that the water does not come to a boil and scorch the chocolate.
While the chocolate is melting, lightly oil the inside of a 23 cm (9 inch) spring form pan and line the sides with parchment paper.
Then crush the biscuits in a food processor or with a rolling pin until fine and press into the bottom of the spring form pan
Remove the chocolate from the heat when melted to let cook for a few minutes.
Whip the cream until it just thickens softly.
Fold into the chocolate 1/3 of the whipped cream until loosened, then gently folding in the remaining whipped cream until it is completely incorporated.
Spoon into the prepared spring form pan, smooth the top and tap on the counter to make sure that you do not have any large air bubbles trapped in the mixture.
The cakes top will be the finished cakes bottom so be sure that you smooth and level the top of it before you place it in the fridge.
Wrap in plastic wrap and leave in the fridge over night.