A fuel nozzle assembly for a combustor in a gas turbine including: a gaseous fuel passage and a fuel nozzle at a distal end of the passage; an air tube concentric with the fuel nozzle and defining an air passage between the air tube and the fuel nozzle, wherein the air tube includes a distal section extending axially beyond the fuel injection nozzle; a first fuel-air mixing zone inside the distal section of the air tube, wherein the first fuel-air mixing zone is downstream of the fuel injection nozzle; a flame holder including a porous structure with thermal barrier coating and micro swirlers and defining a downstream end of the first fuel-air mixing zone, wherein fuel and air from the first fuel-air mixing zone pass through the porous structure of the flame holder and into a combustion zone of the combustor.