Place one layer onto a serving dish, and pour over just under a quarter of the cooled ganache. Spread to the edge, and then scatter over a quarter of the cookies and marshmallows, tearing the marshmallows in half to distribute. Torch the marshmallows carefully using a kitchen blow torch according to the manufacturer’s instructions.
Repeat with another layer of cake, ganache, cookies and torched marshmallows.
Repeat once more with another layer of cake, ganache, cookies and torched marshmallows.
Finish with a final layer of cake, extra ganache, cookies and extra marshmallows and torch until golden. Serve and bask in the praise of your lucky guests!