Prepare the pastry: In a food processor, pulse the plain flour, icing sugar, and butter until it resembles coarse breadcrumbs. Add the egg and lemon zest, then pulse again until the dough forms. Wrap in cling wrap, resting it in the fridge for about 1 hour.

Preheat the oven: Set your oven to 180°C (356°F) and grease your tartlet moulds generously with butter.

Roll out the pastry: On a lightly floured surface, roll out half of the chilled pastry until it's about 3-4mm thick. Cut into rounds suitable for your tartlet moulds, and line them carefully. Chill in the fridge for another 15 minutes.

Bake the tart shells: Bake the lined tart moulds for 15 minutes, or until the pastry is crisp and slightly browned. Allow them to cool completely before removing from the mould.

Soak the rice: Wash and soak the rice for a good two hours, then drain the water and coarsely grind it to enhance its texture for the phirni.

Cook the milk: In a kadhai, heat the ghee and add the full cream milk. Bring it to a boil and then mix in the ground rice along with the saffron strands.

Simmer to perfection: Lower the heat and let the mixture simmer until the milk reduces by half and the phirni thickens beautifully. Just before turning off the heat, stir in the sugar and kewara water for added flavor.

Chill the phirni: Set aside the phirni to cool, then mix in the additional lemon zest before refrigerating until it's fully chilled.

Assemble the tartlets: Fill each tart shell with the cooled phirni and elegantly top with pista flakes and dry rose petals. Refrigerate them for about an hour before serving to allow the flavors to meld.

Serve chilled: Once ready, serve these beautiful Kesar Phirni Tartlets chilled, and watch the delight on everyone's faces!