Using your fingers, coat the corners and sides of the pan. Move the pan to the bottom level and bake for 20 minutes more, or until a toothpick comes out clean when inserted into the center of the batter. Remove from the oven and let cool. Cut into small squares or diamonds and serve warm or at room temperature. Makes approximately 35 squares.
Barberries are tart red cranberrylike berries.
You can substitute dried cranberries. The rose petals used in Persian cooking are not the same as the commercially grown flowers found in the United States. Do not substitute flowers or rose water.