Abstract: An apparatus and method for cooking portioned food pieces in batches are disclosed. The apparatus comprises a cooking chamber for cooking the food pieces and a water removal chamber, beneath the cooking chamber, having a wastewater outlet, for discharging hot wastewater from the water removal chamber. A heating chamber is arranged around the cooking chamber, with a heating unit being arranged between the heating chamber and cooking chamber. A fresh water tank is connected to the heating chamber in order to fill the heating chamber with fresh water, and the heating chamber is connected to the cooking chamber to fill the cooking chamber with preheated fresh water. A wastewater tank is connected to the wastewater outlet. The wastewater tank and the fresh water tank are configured such that the fresh water in the fresh water tank is preheated by the hot wastewater in the wastewater tank.