Preheat the oven to 180°C.
Grease and line two 20cm sandwich tins with parchment and dust with flour.
Cream the butter and sugar in a mixer until pale and fluffy.
Beats in the eggs gradually, then mix in the flour and orange zest.
Divide the batter between tins and bake for 25-30 minutes until golden.
Cool the cakes in the tins briefly before transferring to a wire rack.
Heat raspberries, orange juice, and sugar in a saucepan for 15-20 minutes.
Set the jam aside to cool completely.
Beat butter, icing sugar, orange juice, and zest until smooth.
Assemble the cake by layering sponge, icing, jam, and the second sponge.