To make the shortbread, beat the butter and icing sugar together in a medium sized bowl with a hand-held beater until pale and fluffy.
Add in the zest of 2 lemons, along with 1 teaspoon of lemon juice and continue to beat for another minute until incorporated.
Sift the flour and add this to the butter mixture along with the poppyseeds, then fold through until a dough comes together. Wrap the dough in cling film, flatten slightly and chill in the fridge for 30-40 minutes.
Now preheat your oven to 180°c bake and line a baking tray with grease-proof paper, then set aside.
Once the dough has chilled and the oven is up to temperature, turn dough out onto a flour surface and using a rolling pin, roll dough to 1cm thick. Cut into desired shapes using a knife or cooking cutter.
Place shapes onto prepared baking tray and bake for around 15 minutes or until the edges are sightly golden in colour. Remove from the oven and allow to cool slightly before moving to a cooling rack to cool completly.
To make the frosting, beat together the butter and cream cheese until pale and fluffy, about 3-5 minutes. Add in the icing sugar and continue to beat for another few minutes.
Finally, add a small bit of lemon juice at a time until the desired consistency has been reached. Then pipe, blob, of cover the top of your shortbread with a smooth layer of frosting.