From the Book "Sweet" by Yotam Ottolenghi and Helen Goh
Preheat your oven to 180ºC (160ºC if you are using a fan setting)
Grease and line a 23cm springform cake tin
Crush the cardamom pods and take out the seeds and place in a food processor.
Add the pistachios and blitz until the mixture is finely ground. Transfer to a bowl and add the ground almonds, semolina, baking powder and salt (if using unsalted butter) and mix together and set aside.
Put the butter and sugar into an electric mixer bowl with a paddle attachment and beat on medium high until fully combined. Do not overwork as you don't want to get too much air into the mix. While the machine is running slowly add the lightly whisked eggs in a few batches. Make sure each batch is incorporated before adding more egg. Scrape down the sides of the bowl. The eggs will curdle slightly.
Remove the bowl from the machine and add the dry ingredients, folding them in gently. Once again do not over mix. Fold in the lemon zest, lemon juice, rosewater and vanilla extract.
Pour the batter into the prepared tin and level the top. Bake for 55-60 minutes or until a skewer inserted into the centre comes out clean but oily. You need a nice dark golden, firm crust on this cake because you are now going to pour a lot of syrup onto it.
As soon as the cake comes out of the oven drizzle the syrup over the top. There is a lot of syrup, but use it all. Sprinkle the pistachios over the cake whilst it is still wet, which will help the nuts to stick.
Allow the cake to come to room temperature before taking it out of the cake tin. Sprinkle with crystalised rose petals. and serve with the prepared cream.
About 10 minutes before the cake is going to come out of the oven start making the syrup. Place all the ingredients in a small saucepan over a medium heat and bring to the boil, stirring so that the sugar dissolves. Remove from the heat. The consistency is very watery and all this syrup is going to be poured onto the cake.
Whisk the yoghurt, creme fraiche and icing sugar together, together with the rose water (optional). Serve a generous spoonful with each slice of cake.
Brush each petal with whisked egg white and dip into castor sugar. Shake off excess sugar. Place on a lined baking sheet and dry out in the oven at 100ºC for about 20 minutes until crisp and dry