01 - Preheat oven to 340°F and butter an 8-inch round cake pan. Line with parchment paper for easy removal.
02 - Beat softened butter and caster sugar in a large bowl until pale and fluffy, approximately 3-4 minutes.
03 - Add eggs one at a time, beating thoroughly after each addition until fully incorporated.
04 - Fold in Greek yogurt, fresh lemon zest, and rosewater until combined.
05 - Whisk together ground almonds, flour, cardamom, baking powder, and salt in a separate bowl.
06 - Gently fold dry ingredients into wet mixture until just combined, being careful not to overmix.
07 - Pour batter into prepared pan, smooth top, and bake for 40-45 minutes until a skewer inserted in center comes out clean.
08 - Let cake rest in pan for 10 minutes, then transfer to wire rack to cool entirely before icing.
09 - Whisk icing sugar with rosewater, adding liquid gradually until thick but pourable consistency is achieved.
10 - Drizzle icing over cooled cake, then immediately sprinkle with chopped pistachios and dried rose petals.