To make the slice
Line a slice tin with baking paper, making sure to leave paper hanging over the sides.
Place the biscuits inside your thermomix bowl and crush for 5 seconds on speed 9. Pour the crushed biscuits into a separate bowl and set aside.
Add the butter to your bowl (no need to clean it) and cook for 2 minutes at 60 degrees on speed 2.
Add the condensed milk, lemon juice, coconut and biscuits to the bowl and mix for 15 seconds on speed 4, or until combined. Use your spatula to help scrape the sides of your bowl mid way through mixing.
Pour the mixture into your prepared slice tin and use the bad of metal spoon to spread it across the tin.
To make the icing
Place all the ingredients into your clean thermomix bowl and mix for 30 seconds on speed 4. If your icing is too thick, add an extra 1/2 teaspoon of water to the mixture until it is a spreadable consistency.
Pour the icing over the top of your slice and decorate it with the extra coconut.
Place the slice into the fridge for 6 hours (preferably overnight) or until set.