An apparatus for preparing a beverage fit for consumption with a fine-bubble froth layer, in particular cappuccino. The invention provides a beverage unit, which dispenses under pressure a beverage to be processed to a beverage processing path, through which, in use, the beverage flows to obtain the beverage with the fine-bubble froth layer. The beverage processing path successively includes a nozzle and a buffer reservoir, the nozzle being positioned relative to the buffer reservoir such that, in use, it generates a liquid jet squirting into the buffer reservoir to obtain the beverage with the fine-bubble froth layer. The buffer reservoir is provided with an outlet path for discharging the beverage from the buffer reservoir, the liquid flow path, upstream of the nozzle, further including an additive holder which, in use, can be filled with a product to be dissolved in the beverage, such as concentrated milk or milk powder. In use, beverage leaving the beverage unit flows into the additive holder to dissolve the possible additive in the beverage. The additive holder is provided with an outlet path, via which the beverage is further transported from the additive holder to generate the jet of the beverage.