A method of producing a semifinished confectionary product, such as chocolate or similar, using at least one centrifugal unit for simultaneously grinding and mixing at least some of the ingredients of the semifinished product, and which includes an elongated processing chamber with a substantially horizontal axis, at least one inlet for the ingredients to be processed and one outlet for the processed ingredients, and a powered shaft fitted inside the processing chamber, coaxially with the axis, and fitted with a succession of radial appendixes arranged between the inlet and the outlet; the method including the steps of loading at least a first ingredient of the semifinished product through the inlet; grinding the first ingredient inside the grinding and mixing unit by rotating the shaft at a first speed; loading at least a second ingredient through the inlet, after grinding; rotating the shaft at a second speed to grind and mix the ingredients to form a mixture of the same grain size as the semifinished product; loading at least a third ingredient through the inlet; mixing the third ingredient with the previously ground mixture to form a further mixture; bringing the further mixture to a given temperature to obtain the semifinished product; and transferring the semifinished product to a storage or packaging station.