Put the crushed biscuits in a bowl and stir in the melted butter until absorbed. Press the biscuit mix into the bottom of a large, greased springform tin, then pop in the fridge (1 hour) or freezer (20 minutes) until set - it should feel very firm to the touch.
In a large bowl, lightly whip the cream cheese then whisk in the Baileys. In a second large bowl, whip the double cream with the icing sugar until you have stiff peaks.
Tip the cream cheese mix into the whipped cream and gently fold until fully combined.Fold in the flakes.
Spoon the filling onto the biscuit base and smooth over the surface. Refrigerate for at least two hours but ideally overnight.
Once set, run a warm knife around the inside of the tin before unclipping, then remove the cheesecake, transfer to a stand or plate and decorate with cocoa powder dusted over the top.