Preheat the oven to 325F. A lower temperature is used so we don't want too much browning on the outside. Grease the cake tin thoroughly.
Powder the pistachios (if it is not readily available)
Make the buttermilk - Combine milk and lemon juice together. Cover and rest it for 10 mins. Mix in rosewater, sugar, and oil. [Refer notes]
Combine all dry ingredients. all-purpose flour, almond flour, powdered bread slices, pistachio powder, baking powder, baking soda, & salt.
Pour wet ingredients over dry ingredients and then mix well.
Pour the batter onto cake tin & bake for 50-55 mins or until toothpick comes out clean.
Make sugar syrup - Combine water, sugar, saffron strands, & lemon. Mix well. Boil the syrup for 5-8 mins. Next, stir in pistachio powder & rose water. Make sure there are no lumps.
Place the cake on a wired rack - Allow the cake to cool down for 10 mins on the tin, and then transfer it to a wired rack.
Dunk the cake with syrup - Before you start the pour, place a plate below the wired rack to collect the extra syrup that falls off the cake. Pour the syrup all over the cake and then let it drop the excess syrup. Collect it, and use the syrup to pour again all over the cake. I did this twice. There will be more syrup left. Allow the cake to cool down completely.
Once the cake is cooled down, slice the cake and pour the remaining syrup all over the slices. This will ensure that cake is coated thoroughly with syrup.