Grease and line a 22cm X 32cm rectangular slice tin with baking paper.
Cut the lime rind off with a sharp knife. Place the lime rind into the TM bowl and chop finely on Speed 8 for 50 seconds or until it has a finely grated feel (you will need to scrape down the sides of the bowl a few times).
Add the biscuits and crush on Speed 7 for 5-10 seconds or until the biscuits resemble fine crumbs. Set the biscuits and lemon rind aside.
Place the butter into the TM bowl and melt on Speed 3, 60 degrees, 2 minutes (you may need to scrape the sides of the bowl down with a spatula after 1 minute).
Add the condensed milk and lime juice. Mix on Speed 3 for 5 seconds until well combined.
Add the dry biscuit mixture and the coconut to the TM bowl. Mix all ingredients together on Speed 4 for 5 seconds. Scrape down the sides with a spatula and mix again on Speed 4 for an extra 10 seconds.
Firmly press the mixture into the prepared tin and place into the fridge.
Place the icing sugar, butter and lime juice into the TM bowl and mix on Speed 4 for 20 seconds. Scrape down the sides of the bowl with a spatula. Mix on Speed 4 for an extra 30 seconds.
Spread the frosting over the slice, sprinkle with the extra coconut and place back into the fridge to set completely.
Cut into slices.Store in an airtight container in the fridge for up to 1 week.