For custard:-
In a bowl add custard powder and milk mix it well properly.now custard paste is ready.

Now in a bowl add milk,sugar and custard paste mix it well and boil for 10 min.on low flame.custard milk is ready.

For coffee:-
Now in a bowl add milk add sugar, coffee powder

Mix it well and boil for 5 min.on low flame and whisk for 5 min.now coffee is ready.

Now in a chilled custard milk and chilled coffee and beat for 5 min.on low to high speed in a beater machine.

Now custard coffee milk shake is ready to serve.