Bryan Cranston has been praised to no end for his portrayal of cancer-ridden teacher turned meth cook. Part of what makes the show so successful is how real it feels, and with good reason: Bryan Cranston actually learned how to cook meth in preparation for the show!
The producers hired some DEA chemists to serve as consultants on the show. Part of what they showed the actors was the real process to cook meth. Although he implied it, Cranston said he didn't cook real meth, although hypothetically, it would've been really good.
Cooking the drug, as fans of the show know, is actually a very difficult process because there are so many volatile components that can explode and severely hurt the cook.
Check out the interview on YouTube for more.