01 - Preheat oven to 340°F (170°C). Generously butter an 8-inch round cake pan and line bottom with parchment paper.
02 - In a large mixing bowl, beat softened butter and caster sugar with electric mixer until pale and fluffy, approximately 3-4 minutes.
03 - Add eggs one at a time, beating thoroughly after each addition until fully absorbed and mixture is smooth.
04 - Fold in Greek yogurt, fresh lemon zest, and rosewater until evenly distributed throughout batter.
05 - In separate bowl, whisk together ground almonds, flour, cardamom, baking powder, and salt until well blended.
06 - Gently fold dry ingredient mixture into wet batter using spatula, mixing only until flour disappears. Do not overmix.
07 - Pour batter into prepared cake pan, smoothing top with offset spatula to ensure even surface.
08 - Bake for 40-45 minutes until golden brown and wooden skewer inserted into center emerges clean.
09 - Let cake rest in pan for 10 minutes before removing. Transfer to wire rack and cool completely before icing.
10 - Whisk icing sugar with rosewater in small bowl, adding liquid gradually until thick but pourable consistency is achieved.
11 - Drizzle icing over cooled cake, allowing it to drip down sides. Immediately sprinkle with chopped pistachios and rose petals while icing is wet.