<p>A cooking chamber (3) is provided with a muffler (5) and a bottom muffler opening (6). A lower door (17) with a cooking section (15) on the upper side closes the muffler opening. At least one preselected mode of operation is set in the closed position of the lower door and at least one other preselected mode of operation is set in the open position of the lower door. A preselected mode of operation is thereby activated after the lower door is set in the closed or open position.</p>
