Melt the butter, sweetened condensed milk and Turkish Delight chocolate in a Thermomix bowl on 60 degrees, 4 minutes, Speed 2.
Add the plain sweet biscuits and mix on Speed 5, 5 seconds to crush.
Add the desiccated coconut and Turkish Delight chunks and mix on Reverse, Speed 4, 10 seconds.
Pour mixture into an 18X28cm lined rectangular slice tin and press down hard.
Melt the white chocolate and vegetable oil in a clean and dry Thermomix bowl on 50 degrees, 3 minutes, Speed 2. Spread the melted chocolate evenly over the slice.
Place drops of food colouring onto the chocolate and use a skewer or a knife to make swirly patterns.
Pop into the fridge until the chocolate is firm. Cut into squares.
Place in an airtight container and store in the fridge for up to 5 days.