Thinking LSAT, Powerscore LSAT, LSAT Unplugged, and Law to Fact are some examples. The founder of LSAT Unplugged has a great story of going from struggle to mastery.
I believe its this lesson! https://7sage.com/lesson/mastery-embedded-conditional/
It falls under the "Advanced Logic" course. There is another lesson afterwards which shows the proof of it as well :)