Preheat the oven to 180ºC/350ºF/gas 4. Grease and line the bottom and sides of a 20cm springform cake tin with greaseproof paper.
Using an electric whisk, beat the butter with the caster sugar until light and creamy. Add the eggs one by one, beating each in well. Fold in your ground almonds, poppy seeds, the lemon zest and juice and the sifted flour. Spoon the mix into the prepared cake tin and bake in the preheated oven for 40 minutes or until lightly golden. You can check to see if the cake is cooked by poking a cocktail stick right into the sponge. Remove it after 5 seconds and if it comes out clean the cake is cooked; if slightly sticky it needs a little longer, so put it back in the oven. Allow the cake to cool on a rack.
Make your lemon syrup by heating the sugar and lemon juice in a pan until the sugar has dissolved. While your cake is still warm, make lots of little holes in the top with a cocktail stick and pour your syrup over.
To make your icing, sift the icing sugar into a bowl and add the lemon zest and juice, stirring until smooth. When your cake is almost cool, put it on a serving plate and pour the icing carefully over the top. If you pour it on to the middle of the cake, then let gravity disperse the icing down the sides, you get the ‘drizzle’ effect! Give it a helping hand with a spoon if you want.