Preheat oven at 180°C.
Heat milk in a deep non-stick pan and bring it to a boil. Simmer, stirring continuously, till it reduces half the quantity.
Break 8-9 flaky pastries into two and place in a square glass baking dish.
Reduce heat and add condensed milk in the pan. Keep stirring and reduce for another 5-10 minutes.
Switch off heat and pour half the reduced thickened milk over the flaky pastry in the baking dish.
Add castor sugar, 1 tablespoon chopped walnuts, 1 tablespoon chopped almonds and 1 tablespoons chopped pistachios on top.
Break remaining flaky pastries into two and place on top covering the milk. Pour the remaining reduced milk all over. Add remaining chopped pistachios, almonds and walnuts on top.
Put the dish in the preheated oven and bake for 10-15 minutes.
Garnish with shredded rose petals and serve warm.