“We have a ZZ Top recording studio in Texas called Foam Box Recordings. It’s a humble little place to gather. After our months in Malibu, we reconvened at Foam Box to get some work done. Dusty asked me about the stuff I’d done with Rick and The Black Keys – we had seized a golden opportunity when we were all together – and he said, ‘Could we do one of those songs?’ And I said, ‘Why not?’ He happened to have one of the tracks on the CD player, but when he hit play it wasn’t The Black Keys, it was a completely different thing. It was a song that Rick had suggested we take a stab at, a Gillian Welch composition, It’s Too Easy – that’s the original title.

“It’s a very complex composition. Frank and Dusty kind of shy away from getting too academic; they don’t like to read charts. So they said, ‘Let’s just learn it.’ And I said, ‘Guys, this is complicated. It’s gonna take a lotta, lotta practice.’ They were like, ‘Aw, no, we can get through it.’ Well, it took two hours just to get the first verse.

“I said, ‘OK, we’ve got the first verse. Do you think we can take a stab at the next movement?’ This would be the solo section. Well, that was another two, two and a half hours. Now we’re getting weary. And what happened was, we learned the second movement and forgot the first! [laughs]

“We took five, everybody took a deep breath and came back in. This time, though, I said, ‘Instead of charging back into this hard-to-crack nut, Frank, give me a simple shuffle. Give me a good bluesy shuffle – Texi backbeat.’ Which he did, and I started into a guitar figure, and Dusty perked up. It kind of sounded a little like Tush. Dusty said, ‘I can do that. What key?’ And I said, ‘Key of C. Let’s fall in!' I’m getting the thumbs up from Mr. Moon, and we’re capturing this thing full-tilt.

“Only problem was, it was for 90 seconds. Frank and Dusty kind of threw in the towel and said, ‘You know what? We’re beat. Let’s pick this up tomorrow.’ Everybody folded the tent, Frank and Dusty split, and I went back into the control room. Well, wouldn’t you know, Mr. Moon looked at me and said, ‘Well, doggonit, we got it!’ I said, ‘What do you mean? We only played for a minute and a half.’ And he said, ‘That’s OK. All of the movements are intact. We can build a song out of this.’

“That was the first inkling that it was going to work, and it became the song Chartreuse. I stuck around and expanded on it. The next day the guys returned and they wanted to take another stab at it. Dusty said, ‘Well, what do we call this thing?’, to which Mr. Moon said, ‘Call it Chartreuse. First off, it’s a liqueur, and secondly, it’s an oddball color, and that’s what you guys are!’

“So it was born out of us trying to play the Gillian Welch song. There’s an abrupt ending, which is one of the few things a perfectionist might want to take issue with – ‘Can’t you guys get a more elegant stop point?’ But we left well enough alone and kept the excitement value.

“For the solo, I discovered that we had written a section in two different keys, and I don’t know how to play a solo that jumps from key to key without weeks of practice in order to get it polite. So, in short order, I knocked it out. It’s pretty well seamless. The bonus was playing the ’61 Les Paul that I got from George Gruhn. What an excellent-sounding machine.”