Sift the flour, baking powder and salt into a large bowl.
Add the ground almonds and caster sugar and mix.
Mix the eggs, honey, yoghurt, sunflower oil and lemon zest together well in another bowl.
Make a well in the center of the dry ingredients and slowly pour in the wet ingredients, bringing them together with a whisk until they are just combined.
Add some chopped pistachios to the mixture.
Pour the mixture into the 22cm springform cake tin lined with greaseproof paper and bake in the oven at 180C for 50 minutes or until a skewer inserted into the middle comes out clean. Allow to cool in the tin for about 20 minutes.
Meanwhile, make the syrup. In a small saucepan, boil the water and sugar for about 5 minutes until it is reduced by half.
Add the lemon juice and boil for a further 2 minutes, then cool and add the rosewater.
Make holes on top of the warm cake with a toothpick and spoon the syrup all over the top. Scatter the pistachios over and leave to cool for 1 hour.