Combine smashed chocolate cake and condensed milk in a deep bowl and mix well.

Divide the mixture into 5 equal portions and roll each portion into balls.
refrigerate for 15-20 mins.
Now dip the balls into melted chocolate.

After that, quickly dip into cake sprinkles so that it will stick to the chocolate.

Now again, refrigerate them for 10 mins.
At last, just see to it that chocolate balls should not melt in room temperature.
Finally, your christmas chocolate balls are ready.