Abstract: A cooktop panel having a throughgoing main mounting hole and upper and lower faces has a burner having a holder underneath the panel, engaging the lower face at the hole, and provided with a gas inlet and a gas nozzle and a burner head mainly above the panel, engaging the upper face at the hole, and forming a downwardly extending intake passage into which the nozzle can feed gas. Fasteners engaged through the panel between the holder and the head retain the holder and head against the respective lower and upper faces. A burner cover atop the burner head forms therewith an annular gas-distribution chamber comunicating with the passage and forms with the burner head an annular array of outlet openings. This cover in formed with an upwardly projecting rack-centering collar defining a central seat. A rack atop the cover is formed centrally with a centering pin engaged in the seat. The holder is formed with a radially projecting mounting arm in turn formed with at least one vertically through-going igniter hole.