Lemon Gateau

For the cake: heat the oven to 180°C (160° fan) 350°F gas 4. Grease 2 x 20cm|8" deep loose-based cake tins and line the bases with non-stick baking paper.

Beat the butter and sugar in a mixing bowl until light and fluffy.

Add the eggs, beating well to combine. Add the flour, lemon zest and juice and mix well.

Spoon into the tins and bake for 30-35 minutes until golden and springy to the touch. Cool in the tins for 10 minutes, then place on a wire rack to cool completely.

For the filling: beat the butter until soft. Sift in the icing sugar and beat until until light and fluffy, then beat in the lemon juice and food colouring.

Turn one cake upside down and spread with the lemon buttercream. Place the other cake on top.

For the frosting: whisk all the ingredients together until smooth.

Put the cake on a plate and spread the frosting over the top and sides. Chill until ready to serve.

To decorate: heat the water and sugar in a pan over a low heat until the sugar has dissolved completely. Add the lemon slices and bring to a boil. Reduce the heat, cover and simmer for about 20 minutes, until the lemons are tender. Set aside to cool completely.