Pre-heat the oven to gas mark 4 (160 C), and line three 7 inch cake tins with grease proof paper.

In a large bowl, whisk together the butter and the sugar until soft.

Beat in the eggs one at a time and beat well until the mix is creamy and pale.

Cut the vanilla pod in half and scrape out the seeds into the bowl along with the lemon zest then mix until combined.

Sift the flour into the bowl and fold through until the flour is fully incorporated.

Pour the cake mix into three separate cake tins and bake for 35 mins until springy to the touch and a skewer comes out clean.

Allow to cool in the tins for 10 minutes before turning out on to a cooling rack.

Once the cakes have cooled completely, it's time to make the buttercream.

In a large bowl, beat together the butter, icing, and lemon juice.

Place 3/4 of the icing into a large piping bag with a big round open nozzle.

Divide the rest between 3 bowls and colour 3 different shades of blue. Place into 3 different icing bags with different star tips.

Using some of the plain icing as "glue" place the bottom cake layer onto a cake board.

Pipe a ring of icing around the top edge of the layer.

Cover the rest of the top of the layer with blueberry compote.

Place the second layer on top and repeat the ring of icing with blueberry compote filling.

Put the final layer on top.

Crumb coat the cake making sure you have a smooth base coat and all gaps between the layers are full.

Use the remaining plain icing to cover the cake completely with a smooth finish.

Take the 3 coloured icing bags and start by piping roses then clusters of the smaller flowers.

Finish with sprinkles or fresh flowers if desired.