In a medium size saucepan, add sweet potatoes with water and boil on low heat until done.
Once done set aside and let it cool down.
Drain water from sweet potatoes and peel, set aside.
In another saucepan, add milk and bring to a boil.
Once boiled let the milk cool down.
Now in a mixing bowl add milk, banana, sweet potato, and sugar. (add milk depending upon the required consistency)
Now mash the riped banana and sweet potato with hand so as to form a nice paste.
If you have fresh cream available then you can top it up with fresh cream while serving, as it tastes great.
Serve hot or chilled. (I prefer having it chilled)
You can serve it for breakfast or as a dessert.
Kids will love it.
Notes
If you want you can boil sweet potatoes in the pressure cooker as well, just like the potaoes. You can increase or decrease the quantity of any of those 4 ingredients as per you requirement. If you want some different flavor then you can add little cardamom powder to it.