Crush Marie biscuits into as fine a powder as you can. You can do this by running the biscuits in a food processor or put them in a Ziploc bag, seal and then bash them with a rolling pin.

Whip the cream and lime juice using a hand held electric beater to soft peaks. It helps if you do this over a larger bowl filled with ice cubes and a little water. Add the vanilla extract and half the condensed milk. Continue whipping and add as much more condensed milk as you need (according to preferred level of sweetness) . Keep beating till until the mixture forms reasonably stiff peaks.

Transfer the cream into a piping bag and pipe (or spoon the cream if you can do it neatly) it equally between 4 serving glasses, alternating layers of cream and crumbled biscuits. Finish of with cream as the topmost layer.

Refrigerate for at least 4 hours or until you are ready to serve the Serradura.