Prue Leith's Le Gâteau Vert recipe - The Great British Bake Off

Ingredients

• 300g pistachio kernels
• 225g icing sugar
• 1 large egg white, whisked
• 1 tsp pistachio essence
• 50g pistachio kernels
• 75g plain flour
• 125g caster sugar
• 4 large eggs
• 25g unsalted butter, melted
• grated zest of 1 unwaxed lemon
• 300g spinach
• 100g pistachio kernels
• 1 tbsp kirsch
• 150g unsalted butter, softened
• 80g caster sugar
• 2 large egg yolks
• 250g fondant icing sugar
• 3–4 tbsp spinach water (see method)
• ½ tsp pistachio essence (optional)
• 25g pistachio kernels
• edible flowers, to decorate