Grease and line the sides and bottom of a 14cm x 24cm loaf tin with baking paper.
Preheat oven to 160 degrees celsius (fan forced).
Place the softened butter and caster sugar into a large bowl.Beat with hand-held beaters or a stand mixer until pale and fluffy. If using a Thermomix: Place the butter (chopped into chunks) and caster sugar into the Thermomix bowl and and mix for 15 seconds, Speed 5. Scrape down the sides of the bowl.
Add the eggs, one at a time, beating well between each addition.If using a Thermomix: Reduce to Speed 2 and add the eggs (one at a time) through the MC hole.
Sift over the gluten free self raising flour, baking powder, xanthan gum and add the lemon zest. Mix until well combined. If using a Thermomix: Add the gluten free self raising flour, baking powder, xanthan gum and lemon zest and mix for 10 seconds, Speed 4. Scrape down the sides of the bowl and repeat for a further 5 seconds.
Pour the mixture into the prepared loaf tin and smooth the surface.
Bake for 45 minutes or until a skewer inserted into the middle comes out clean (don't overcook the cake as you want it to be deliciously moist).
To Make The Lemon Drizzle
While the cake is still warm, prepare the lemon drizzle by mixing together the lemon juice and caster sugar in a bowl.
Carefully poke holes all over the cake with a skewer (to allow the lemon drizzle to soak in).
Pour the lemon drizzle over the top of the cake.
Notes
RECIPE NOTES
Use room temperature ingredients - they blend together easier than cold ingredients, creating a smooth batter.
Don't overcook the cake - you want it to be deliciously moist.
If your lemon cake is browning on top - just place a loose sheet of foil over the baking tin.
Your cake is ready - when a skewer inserted into the middle comes out clean or with just a few moist crumbs on it.
Storing - you can keep this cake in an airtight container at room temperature for up to 4 days or store in the fridge for up to 7 days. Bring to room temperature before serving (as the fridge will dry the cake out).
Freezing - you can also freeze this cake for up to a month - simply wrap in plastic wrap and then a layer of foil, either whole or in slices.