Place the white chocolate into the Thermomix bowl and mill 10 sec/speed 10. Scrape down sides of bowl.
Melt chocolate 20 min/40°C/speed 1. Stop periodically and scrape down sides of bowl. Add lavender oil or other oil of choice.
Meanwhile line a large flat baking tray with either a silicone mat or baking paper.
Divide the melted chocolate into two batches and colour one of them, stirring vigorously to combine.
Spread the white chocolate onto one end of the prepared tray. Place the coloured chocolate on the other end and swirl them to combine. Tap the tray gently on the bench to level the chocolate then go to town with all the decorations. Start with the ruby callets, and finish with the sprinkles. Refrigerate to set and then chop into pieces and wrap for gifting.