Hill with a ramp leading to the top

Hey everyone.
I need to model a hill with a slope ramp that starts from the top and, rolling around the side, goes all the way to the top. Bad drawing to let you see what I mean.


I need for this to be in a low poly style, it probably will be in a game with an unlit shader (or anyway non photorealistic). How can I make it? I tried the screw modifier, but not sure is the way to go :confused:

Have a good day!

Hereโ€™s one way. Could adjust the spiral slope as a curve (proportional editing in connected mode) before converting to mesh

Used addons Curve: extra objects to make the spiral, and F2 to fill.

simple screw: