1. Cream together your butter, sugar and lemon zest until your mixture is light and fluffy.
2. Carefully fold in the flour and bring your dough together with your hands if needed.
3. Flour your surface and roll out your dough to the thickness of about a pound coin, cut out your desired shapes and leave on a baking tray. Make sure not to overwork your shortbread dough!
4. Poke your shortbread with a fork and sprinkle with some caster sugar.
5. Leave your cookies in the fridge for 20-30 minutes, then bake for around 15 minutes in a preheated oven at 150C fan.
6. Once baked and cooled, dip half of your shortbread in some melted chocolate and finish topped with some crushed pistachios.