After about 12/16 minutes (depending on the desired consistency of the rice), turn off the heat and add the mascarpone (taken directly from the refrigerator), add also the grated Parmesan and stir quickly and intensely to achieve the desired creaminess. At this stage it may be necessary to add a little extra water. Taste and check the saltiness, and possibly adjust if necessary. If no salt was added to the water previously, some fine or flaked salt may be added at this point. Add a few drops of lemon juice.