This will unlock after you complete challenge #7 in Stage 2 of the Mission Challenges. There’s only the one.
I found it tough to get gold with auto-drive braking on as it would slow you down too much in the corners. So I would recommend doing it with auto-drive off. You could also practice a few laps with it on if you’re having trouble and then once you’ve learned the course turn it off and you should be faster.