The invention relates to a device for metering out a flowable mass, especially a mass containing fat, for producing confectionery products, for example to a nozzle for extruding a mass into a mold. The mass traverses an inlet opening (13) and enters a chamber (8) from where it can be extruded through an outlet opening (14) by means of a plunger (7). A rotary piston (12) is associated with the plunger (7) and closes the outlet opening (14) in a position of use and the inlet opening (13) in a second position of use. The invention is characterized in that the rotary piston (12) has a recessed portion (16 to 19) which extends from a front edge (15) of the rotary piston (12) towards its peripheral surface (25).