Last week, I joined Posse members Marshall Cooper and Jim Rossman for a quick roadtrip to Austin. Marshall was returning a portable smoker to Franklin Barbecue pitmaster John Lewis, who he has been helping on the national BBQ cookoff competition circuit. It was a great excuse to grab a bite at both Franklin and the new JMueller BBQ while we were down there. JMueller BBQ was opened in October by John Mueller, grandson of legendary BBQ master Louie Mueller of Taylor. Much has already been written about the joint, including a New York Times story published before he even opened…