Step 1: Preheat your oven to 170°C (340°F) and grease and line a 20cm (8-inch) round cake tin with parchment paper.
Step 2: In a large bowl, cream together the softened butter and caster sugar until the mixture is light, pale, and fluffy.
Step 3: Beat in the eggs one at a time, ensuring each is fully incorporated before adding the next. Stir in the vanilla extract and orange blossom water.
Step 4: In a separate bowl, whisk together the ground pistachios, flour, baking powder, and salt. Gently fold the dry ingredients into the wet batter until just combined.
Step 5: Pour the batter into the prepared tin and smooth the top. Bake for 40-45 minutes, or until a skewer inserted into the center comes out clean.
Step 6: While the cake bakes, prepare the syrup by combining sugar, water, and lemon juice in a small saucepan. Bring to a boil, then simmer for 5 minutes. Remove from heat and stir in the crushed saffron and orange blossom water.
Step 7: Once the cake is removed from the oven, poke holes all over the surface with a skewer. Pour the cooled syrup over the hot cake and allow it to soak in completely before removing the cake from the tin.
Step 8: Garnish with extra crushed pistachios and dried rose petals before serving.