Preheat the oven to 170C/325F (fan). Line a loaf tin with a loaf liner.
Mix the vegetable oil and sugar together in a large bowl. Add in the lemon zest, flour, bicarbonate of soda, salt, and milk. Beat together with a wooden spoon to combine. Stir in the lemon juice.
Spoon into the prepared loaf tin and place in the oven for 35-45 minutes until golden and cooked through (you can test this by inserting a metal skewer into the centre of the cake – if it’s cooked, it should come out clean).
Take it out of the oven. Mix together the caster sugar and 2 tbsp of lemon juice. Poke several holes in the hot cake and spoon over the sugar-lemon mixture. Leave to cool in the tin. This first topping adds a more intense lemony flavour and moisture to the cake.
Once cool, remove from the tin and remove the loaf liner.
Place the icing sugar in a bowl and add 2 tbsp of lemon juice. Stir with a whisk until combined. You may need to add a little more lemon juice if you want a thinner drizzle.
Spoon the icing mixture over the cake. Arrange rice paper flowers and butterflies on top.
Cut into slices and serve.
