The method comprises adhering edible coating on food stuff core during subjecting on the food stuff core at high temperature. The edible coating forms a solid casing at room temperature, where powdery coating material is used and the foodstuff core is strongly heated with hot air so that the coating material to be applied adheres in contact with the foodstuff core. The foodstuff core is heated in a coating drum with hot air. The coating drum is held at a temperature that is lower than the temperature at which the coating material begins to change. The method comprises adhering edible coating on food stuff core during subjecting on the food stuff core at high temperature. The edible coating forms a solid casing at room temperature, where powdery coating material is used and the foodstuff core is strongly heated with hot air so that the coating material to be applied adheres in contact with the foodstuff core. The foodstuff core is heated in a coating drum with hot air. The coating drum is held at a temperature that is lower than the temperature at which the coating material begins to change. The foodstuff core is heated in temperature resistant transport band and/or grid made of metal, with hot air. The transport band and/or grid are held at a temperature that is lower than the temperature at which the coating material begins to change. The variation of the coating material caused by increased temperature is gelatinizing, crystallization, melting and/or caramelization. The coating drum, the transport band and/or the grid are equipped with a polytetrafluorethylene coating and with a liquid cooler. The foodstuff provided with the casing is cooled with air. The heating of the cooling medium is exploited for heating the hot air. The foodstuff cores are entire and/or part of edible cores of nuts such as walnuts, macadamian nut, hazelnuts, cashew nut, pecan, almond, pistachio, groundnut and other nuts or nuts and fruits, roasted, dried and/or fresh soya bean seeds, bean, p