The term handvergoldet states that the gilding (the decoration with gold) was done entirely by hand.
Genuine gold can be applied to porcelain in a number of ways, the most common being either the direct use of gold leaf or honey gilding, a process in which powdered gold leaf is mixed with honey to create a mixture that can be applied by brush. Neither method is very easy to master and, of course, requires a lot of manual work, including polishing. A certain galvanic process, often called fusing, is another method using real gold, but this is more of an industrial mass production approach.
All of this is in contrast to fool's gold, which is a mixture of various metals and chemicals, often containing minimal amounts of gold (if any). It is most often found on cheap transfer or stencil decorated items, and an educated eye can often tell the difference between real gold and its look-alike.