First cut a long strip of parchment.

Then cut something similar to a circle. As you can see it is NOT perfect.

Then fold it in half the best you can.

And, fold again.

One more time.

Next, center it on the bottom of the cake pan.

Hold it still, and cut off the excess.

Open it up.

Finally place it in pre-greased cake pan. You can do this with any sized pan.