Line a 18cm X 28cm rectangular baking tray with baking paper.
Place the biscuits into the Thermomix bowl and crush on Speed 8 for 10 seconds. Set aside.
Place the butter, condensed milk and cocoa into the Thermomix bowl and melt on Speed 2, 50 degrees for 3 minutes (or until completely melted).
Add the crushed biscuits, rice bubbles and 1 cup of halved Maltesers. Mix on Reverse Speed 3 for 15 seconds or until completely combined.
Press firmly into tray.
Break the white chocolate into the Thermomix bowl, add the coconut oil and melt on Speed 2, 50 degrees, 3 minutes.
Press the remaining Maltesers into the chocolate.
Store in the fridge for up to 1 week.