Crush the Mint Slice biscuits into the Thermomix bowl on Speed 8, 10 seconds.
Add the cream cheese and mix on Speed 4, 30 seconds, or until completely combined.
Roll the mixture into heaped teaspoon-sized balls and place onto a baking paper lined tray. Place into the fridge or freezer for 30 minutes to firm up.
Slice the spearmint leaves into tiny slithers (you'll get about 5 out of each leaf) and set aside.
Place the chocolate into a clean and dry Thermomix bowl and melt on 50 degrees, Speed 3, 3 minutes (or until melted).
Pour the chocolate into a deep, narrow bowl or ramekin. Carefully dip your mint slice balls into the chocolate mixture with a fork (or 2 small spoons) and place back onto the tray - allowing any excess chocolate to drip off.
Place one red M&M and two spearmint leaf slithers onto the top of each of the balls.
Place back into the fridge to set for 3 hours and then store in an airtight container in the fridge for up to 5 days.