Preheat oven to 180°C and place peanuts onto a lined baking tray and straight into the oven. Roast for 20 minutes, they should be a dark golden brown.
Place still warm nuts into mixing bowl and mill 20 sec/speed 8 until a paste forms. Scrape into a separate heat proof bowl and set aside, but try to keep it warm. I returned this peanut butter to the still warm, but turned off oven while I did the rest.
Place chocolate into the Thermomix bowl and chop 5 sec/speed 6.
Melt 5 min/50ºC/speed 1. It will start to seize, but this is ok.
Add salt and vanilla and 150g of the still warm peanut butter and blend 10 sec/speed 3.
Spread into a small lined tin or container and dollop with the remaining peanut butter, then swirl to combine using a fork or offset spatula. Tap the container on the bench until the top levels and becomes glossy. Sprinkle with additional pink salt flakes. Refrigerate until firm cut into squares and enjoy.
For a deeper more satisfying piece of fudge, use a very small tin...I used an 18 x 13cm glass container, lined with baking paper for easy removal of the set fudge.