Prepare 2 circular cake tins (mine are 20cm) - grease them and cut a circle of parchment paper to sit in the bottom. Preheat your oven to 160C Fan / 180C.

Cream together your softened butter and sugar until lighter in colour and fluffy.

Add in your eggs one at a time mixing in between each briefly, followed by your lemon zest.

Add in your flour, baking powder and xanthan gum and mix it in.

Follow this with your elderflower cordial and mix it in.

Divide the mixture between the two tins evenly.

Bake for around 25-30 minutes (remember never to open the oven until you think they are definitely done). To check if the sponges are cooked, insert a skewer and if it comes out clean, it's done!

Whilst the cakes are in the oven mix together your drizzle ingredients in a small bowl. Once the cakes are baked gradually spoon the drizzle over the top of them and allow to cool in the tin.

Place your butter in a stand mixer (or electric hand whisk if you don't have a stand mixer), mix on its own on a high speed for about 5 minutes. The butter should change from a more yellow colour to being a lot more pale.

Add your icing sugar gradually to the butter (I do this in two stages). I mix each addition of icing sugar for around 3 minutes before adding the second half.

Add your cordial and mix again for a few more minutes.

Carefully place one of your sponges onto your serving plate.

Spread a thin layer of lemon curd on the base sponge and then a thicker layer of buttercream on your second sponge - sandwich them together.

If you want to decorate like how I did, pop the rest of the buttercream into a piping bag with a small star nozzle and then pipe blobs all over the top (and slightly down the sides too if you fancy!) Add some extra lemon curd drops on top too. (you DON'T have to decorate like this - just spread a layer of the buttercream on top if you'd prefer, you might not need quite as much)

Top with a little extra grated lemon zest and enjoy!