Preparation

• Preheat oven to 130C/266F (very low oven). Line 2 x 15cm/6inch tins with parchment on the base and sides. In the bowl of an electric mixer fitted with a beater attachment mix the flour, baking powder, bicarb of soda and sugar together. Whisk the eggs with the buttermilk, lemon zest and lemon flavouring in a jug.
  
• Beat in the butter until smooth. Then add the egg milk mixture until it looks like a cake batter. Divide into the two tins and smooth over the top with an angled palette knife. Bake for 35-40 minutes or until the centre springs back when touched gently. Cool completely.
  
• Beat the butter using an electric mixer for 1 minute or until smooth. Add the icing sugar and beat on low speed at first and then increase and add the lemon juice, pink colouring and citric acid. Beat for 4 minutes or until fluffy.
  
• Place the buttercream into a large piping bag and place the jam into a small piping bag. Place one cake on the cake stand or cake board and pipe concentric circles in icing with gaps in between. In the gaps pipe the raspberry jam. Place the other cake on top and then pipe the frosting over the sides of the cake. Smooth with an angled spatula. Then pipe icing on top and make swirls with the spatula. Smash the frozen raspberries and decorate with the pieces and lemon slices.