Preheat your oven to 350°F/ 180°C / 160°C fan/ Gas mark 4. Line a 9-inch rectangular baking tin with parchment paper.

In a large bowl, cream together the vegan butter and the caster sugar. Mix well until it becomes light and fluffy, and the sugar is properly dissolved into the butter.

Add in the flour, baking powder, soy milk and the elderflower syrup. Fold everything together gently until you have a smooth cake batter. Note that it will be slightly thicker than a typical cake batter.

Gently stir in the lemon juice and the lemon zest.

Transfer the cake batter into your pre-prepared baking tin and use a spoon or the back of a spatula to spread it out evenly.

Bake for 40-45 minutes.

While the cake is baking, mix together the elderflower syrup, the caster sugar and the lemon juice in a small bowl.

Take your cake out of the oven after the time is up. It should be golden brown on top and a skewer through the middle should come out clean.

Pour the drizzle mixture over the cake while it's still warm and use the back of a spoon to make sure it's evenly spread out. Leave it to cool completely.

Mix together the powdered sugar, elderflower syrup and lemon juice. You should end up with a slightly runny icing that is still thick and spreadable.

Spread the icing over the cooled cake, and top with lemon zest or slices if desired. If topping with lemon slices, note that these are only for decoration and should be removed before eating.

Leave the cake for around 30-60 minutes to allow the icing to harden, then cut into squares or slices.