Spread the hazelnuts in a single layer onto a baking tray, and roast for 15 minutes.
While the hazelnuts are roasting, place the flaked almonds into a food processor or high-speed blender, and process for 3-5 minutes, until the oil begins to be released, and a little of the mixture can be formed into a ball.
Add the rest of the marzipan ingredients, and process for another 30 seconds, until everything is incorporated.
Turn out onto a board, and knead for 2-3 minutes, until you have a large, smooth ball. Set aside.
As with the plain marzipan, place the flaked almonds and pistachios into the food processor, and process for 3-5 minutes. When you can make a little ball, add the rest of the ingredients, and process for another 30 seconds. Turn out onto a board, and knead until your marzipan is smooth. Set aside.
By now, the hazelnuts should be done, so place them into the food processor, and melt 25g cocoa butter. Process as before, and then add the rest of the ingredients, and process for another 30 seconds or so, until everything is well-mixed. Turn out onto a board, and knead for 2-3 minutes, until smooth.
Make a Mozart bonbon!
Pinch off a little piece of the pistachio marzipan, and roll into a ball. Take a slightly larger piece of the chocolate nougat, roll into a ball, and flatten. Wrap this around the pistachio ball. Make a ball from an even larger piece of plain marzipan, flatten, and wrap this around the pistachio-nougat ball. Roll the whole thing around in your palms to ensure there are no seams, and the ball is smooth. (See the images within the post.)
Repeat until you've used up all the marzipan and nougat.
Melt together the dark chocolate and 40g of cocoa butter. Once the chocolate has melted, using a cocktail stick, carefully spear a Mozartkugel, and then dip into the chocolate, making sure it's evenly coated. Allow the excess to drip off before placing the bonbon onto a sheet of parchment or baking mat.
Repeat for the rest of the Mozart bonbons, and set aside in a cool place for a couple of hours for the chocolate to harden.
Remove the sticks, and enjoy at room temperature.
These vegan Mozartkugeln will keep in an airtight container for up to 8 weeks.