I use the graphic or the toolbar of photoshop 3.0 to make the chocolate bar. Vectorialize the bitmap e send it to the Roland Versa UV LEF-12
to make in hi quality the bass relief.
The VersaUV LEF-12 is Roland’s first flatbed UV-LED printer capable of printing on the surfaces of two- and three-dimensional objects up to 100mm thick.
I use Eco-UV S flexible UV curable inks, for print not with CMYK but with clear varnish ink. I can produce both a matte or high-gloss finish and also be built up for 3D textures and embossed effects such as Braille or my photoshop toolbar.
In alternative you can use 3D printers or an Uniposca to hand draw your graphic. I show you this solution in another instructables.