Line 6 wells of a muffin tin with 1-2 paper liners. Roughly chop the biscuits and distribute them in the molds.
Mix egg, sugar, vanilla sugar and espresso until creamy. Whip 200g cream until stiff, fold in. Distribute in the molds. Freeze covered at least overnight.
Whip 100g cream until stiff. Decorate tartlets with cream and cocoa!