Preheat oven to 180 degrees celcius (fan-forced). Grease and line the base and sides of a 22cm round cake tin with baking paper.
Place lemon rind into the TM bowl and mill for 10 seconds, Speed 10. Scrape down the sides of the bowl and repeat.
Add the butter and caster sugar and cream together on Speed 5 for 30 seconds. Scrape down the sides of the bowl and repeat.
Reduce to Speed 2 and add the eggs one at a time through the MC hole.
Add the sour cream and lemon juice and mix on Speed 5 for 30 seconds (or until smooth).
Add the self raising flour and the plain flour and mix on Speed 2 for 20 seconds (or until just combined) - please note that you may need to use the spatula to help mix/scrape down the sides.
Pour into the prepared cake tin and place into the oven for 45-50 minutes or until a skewer inserted into the middle comes out clean (or with a few crumbs).
Remove cake from the oven and poke holes all of the top of the cake with a skewer (this will allow the syrup to moisten the inside of the cake).
Place the caster sugar, lemon juice and water into the TM bowl. Cook for 3 minutes, 90 degrees, Speed 2.
Remove the cake from the pan and place onto a wire rack (it's a good idea to place a sheet of baking paper underneath the rack to catch any excess syrup drips).
Use a spoon to carefully pour the syrup over the cake.
Cut into slices and serve.