Abstract: Vegetable matter is composted in an outer drum having an axis for rotation which is disposed horizontally for rotation inside an outer housing. The outer drum and the housing have respective waste inlets which are in communication with each other for receiving waste so that waste which is introduced into the housing is received inside the outer drum. An inner drum having an axis for rotation which is disposed horizontally for rotation of the inner drum is disposed inside the outer drum, and receives waste from the outer drum. A waste outlet in the inner drum discharges decomposing waste into a finishing drawer. The configuration of the outer drum with the inner drum disposed inside, allows for a two-stage decomposition of waste matter, thereby maximizing the capacity of the composter while occupying a minimum of space which is customarily at a premium in the kitchen environment.