01 - Preheat oven to 340°F and butter an 8-inch round cake pan, lining the bottom with parchment paper.
02 - In a large mixing bowl, beat softened butter and caster sugar together until the mixture becomes light and fluffy, approximately 3-4 minutes.
03 - Add eggs one at a time, beating thoroughly after each addition until fully incorporated into the mixture.
04 - Stir in Greek yogurt, fresh lemon zest, and rosewater until combined.
05 - In a separate bowl, whisk together ground almonds, flour, cardamom, baking powder, and salt.
06 - Gently fold the dry ingredient mixture into the wet ingredients using a spatula, mixing until just incorporated and being careful not to overmix.
07 - Transfer batter to the prepared cake pan, spreading evenly and smoothing the top surface with a spatula.
08 - Bake for 40-45 minutes, or until a wooden skewer inserted into the center emerges clean and the cake is golden brown.
09 - Allow the cake to rest in the pan for 10 minutes before transferring to a wire rack to cool completely.
10 - Combine icing sugar with rosewater in a small bowl, adding rosewater gradually until achieving a thick yet pourable consistency.
11 - Drizzle the rosewater icing evenly over the completely cooled cake, then garnish generously with chopped pistachios and dried rose petals.