Allyson Gofton, in her recent book, turns these cookies into rose water scented melting moments and she gives an explanation of what Persian Berenji (Rice cookies) is. I used her recipe and baked a batch of her cookies to discover that her recipe is not the real deal. The traditional ones are not iced and don't crumble, it is more like a shortbread in texture
Here is the recipe ....Use an electric egg beater, cream 250g softened butter and 1 cup icing sugar until light and fluffy. Add 1 medium egg (size 6) and beat well. Add 3 cups rice flour (use fine rice flour, not too coarse. I use Healtherie's Rice Flour found in any supermarket) and 2 teaspoons of baking powder. Beat on high until well mixed. The mixure is quite crumbly at this stage. You can roll the cookie dough into any size and shape you desire. Bake them at 180C fan forced oven until they rise slightly and start to turn golden. Make sure they are not over baked. Keep them in an air-tight container for a month.
If you want to make the Persian version of it...add a tablespoon of rose water to the mix. Sprinkle with poppy seeds and press a flower shaped cookie cutter on each cookie before baking them.