Can I turn my polenta roll into a bowl of creamy polenta or am i committed to rounds?

Put it through a food mill.

You can! What I do is heat it up in the microwave for about thirty seconds, then either put it in a small pot over the stove top and mush it down with a fork, then add lots of cream and Parmesan cheese, heating and mashing it together until it's the consistency of mashed potatoes.