Since this is my go-to method, I tried it for the two subjects you suggest: "kernel development" and "writing proper C".
Check it out my results:
For the first one, I expect if you watched the top few results (17 minutes: Kernel Basics, 9 minutes:What is a kernel - Gary explains, 43 minutes:Manuel Schölling: Linux Kernel Development for Newbies) you'll be well on your way to learning this information. (The ones I didn't just quote are great too: "Basic Linux Kernel Programming"; "Write and Submit your first Linux kernel Patch"; etc etc etc etc. The whole page of video results is great.)
My second search above was a bit less of a match. The first four results seem too beginner for you, but the fifth result on that page is a 1 hour 40 minute Bjarne Stroustrup (the inventor of C++) talk titled: CppCon 2015: Bjarne Stroustrup “Writing Good C++14”.
So as you can see this method isn't fool-proof (even the result I just mentioned is about C++ rather than C) but in my experience, a fantastic way to learn that has not been mentioned in these comments so far. (There are currently 38 comments in this HN thread and 0 mentions of youtube.)