Grease and line a 20cm square cake pan with baking paper.
Place 2 of the Mars Bars, butter and golden syrup into the TM bowl.
Melt on 60 degrees, Speed 2 for 3 minutes.
Add the rice bubbles and the remaining Mars Bar.
Mix on Reverse Speed 2 for 15 seconds or until completely combined.
Press the mixture into the prepared tin and place into the fridge.
Place the chocolate melts into a clean TM bowl.
Melt on 50 degrees, Speed 3 for 2-3 minutes (scraping down the sides of the bowl occasionally).
Pour the melted chocolate over the slice and place back into the fridge to set.
Cut into slices.