01 - Preheat oven to 340°F and butter an 8-inch round cake pan. Line bottom with parchment paper.
02 - In a large bowl, beat softened butter and caster sugar until pale and fluffy using electric mixer on medium-high speed for 3-4 minutes.
03 - Add eggs one at a time, beating thoroughly after each addition until fully incorporated.
04 - Mix in Greek yogurt, lemon zest, and rosewater until combined.
05 - In separate bowl, whisk together ground almonds, flour, cardamom, baking powder, and salt.
06 - Gently fold dry ingredients into wet mixture using spatula until just combined. Avoid overmixing.
07 - Pour batter into prepared pan and smooth top with offset spatula.
08 - Bake for 40-45 minutes until wooden skewer inserted into center comes out clean.
09 - Let cake cool in pan for 10 minutes, then remove and transfer to wire rack to cool completely.
10 - Whisk icing sugar with rosewater in small bowl until thick but pourable consistency is achieved.
11 - Drizzle icing over cooled cake. Sprinkle with chopped pistachios and dried rose petals before serving.