Quick draw a curve around an existing curve?

The stair builder plugin is sometimes useful as a quick way of doing this kind of thing.

Either draw the curve by hand, or generate the curve somewhere else and then copy-paste it where you need it.

Connect the endpoints with a linedef.

Use Shift+C on that linedef.

Adjust to your liking.

Press Enter.

@Kappes Buur: This gave me interesting outcome, but its not what i meant. I meant the conture to be written inside/outside...