Melt 45gms (half of the bar) of the dark milk chocolate in the microwave for 2 minutes in (20 second bursts)
Pour the milk in a blender, add the melted chocolate & 3 tablespoons of the chocolate sauce. Blend for 30 seconds.
Add 5 scoops of vanilla choc flakes ice cream, 3 cookies & 1 tbsp. of vanilla extract. Blend for a minute till smooth.
Place the whipping cream in a large bowl add 1 tbsp. of icing sugar & half a teaspoon of vanilla extract. Beat together with a hand mixer or a whisk till stiff peaks form. Be careful not to overbeat.
Put the cream mixture in a piping bag with a decorating nozzle.
Pour the milkshake into a tall glass till 3⁄4 full. Decorate the top of the cup with the whipping cream. Top off with the chocolate sauce and chocolate shavings from the remaining piece of chocolate.