Temper your cocoa butter and splash randomly across the prepared mold. Wipe your mold along a towel to remove any excess cocoa butter from the surface edges.
Temper your chocolate and cast your molds, tapping to release any air bubbles. Invert the mold and use your scraper to tap out excess chocolate. Use the scraper to scrape away excess chocolate. Allow to set slightly, then transfer to refrigerator for 10-15 minutes. Remove from fridge and set aside until ready to fill.
Make the caramel:
In a deep, heavy-duty pot combine the milk, sugar, baking soda, salt and vanilla pod. Cook over medium heat, stirring occasionally, until sugar melts and the mixture is foamy in appearance. Keep a close eye on it, as it can foam up and overflow rather quickly.
Continue to cook, stirring constantly, until it changes to a golden brown and is thick enough to coat the back of a spoon. Be patient, it takes a while for the mixture to reduce and thicken.
Remove from heat, remove the vanilla pod and stir in the vanilla beans. Allow to cool then transfer to a piping bag. Pipe a thin layer into the molded bars and allow to set - leave enough space to cap the bars.
Use some of the remaining tempered chocolate to close the bars - pipe or pour a bit of chocolate over the bars and use a scraper to smooth and scrape away excess. Enjoy!