Preheat oven to 170 degrees celsius (fan-forced). Grease a non-stick rectangular loaf pan (approx 23cm x 13cm) well and set aside.
Add the plain flour, baking powder, coconut and salt to the Thermomix bowl. Sift by pressing the Turbo button in 1 second bursts 8-10 times. Set aside in a separate bowl.
In a clean Thermomix bowl, add the the greek yoghurt, caster sugar, eggs, lemon zest, lemon juice and melted coconut oil and mix for 5 seconds, Speed 5. Scrape down the sides of the bowl and mix for a further 5 seconds.
Add the dry ingredients and mix for 5 seconds, Speed 5. Scrape down the bowl and repeat for a further 5 seconds (or until combined).
Pour the mixture into the prepared tin and bake for approximately 45 minutes or until cooked through when tested with a skewer (see notes).
Allow to cool for 15 minutes before transferring to a wire rack to cool completely.
To make the frosting, place the cream cheese, butter and lemon juice into a Thermomix bowl. Mix for 10 seconds, Speed 6. Scrape down the sides of the bowl and repeat for a further 10 seconds or until smooth and creamy.
Add the icing sugar and mix for 10 seconds, Speed 6. Scrape down the sides of the bowl and repeat for a further 10 seconds.
Spread over the cooled lemon coconut loaf and sprinkle with extra shredded coconut and lemon zest (optional).