For the carrot cake: Preheat the oven to 350 degrees F and grease a 9-inch springform cake pan.
In a bowl, whisk the oil, sugars, vanilla and egg together until combined.
In a medium bowl, whisk the flour, chai masala powder, baking powder and salt until well blended. Add the dry ingredients to a stand mixer fitted with a paddle attachment and add the carrots, nuts and dates. Turn the stand mixer on stir and gradually add the liquid ingredients until just combined.
Pour the batter into the prepared pan. Bake until the top of the cake is springy when touched and a toothpick inserted in the center comes out clean, 35 to 45 minutes. Allow to cool.
For the halwa: Add the milk, carrots, cardamom powder and saffron to a large Dutch oven or heavy-bottomed pot and bring to a boil over medium heat. Reduce the heat, then add the raisins and cook, stirring occasionally, until the milk dries up and the raw smell of the carrot disappears, another 15 to 20 minutes.
Meanwhile, add the ghee to a small saute pan over medium heat and allow to melt. Add the almonds, cashews and pistachios and stir to coat in the ghee. Allow to toast, stirring often, about 5 minutes.
Add the paneer, toasted nuts, condensed milk and granulated sugar to the pot with the milk mixture and stir to combine. Pour the mixture onto sheet trays to cool quickly, then refrigerate to cool completely.
For the assembly: Remove the cake from the pan and split into two layers horizontally. Put 1 cake layer back into the springform pan to help with filling the cake. Put 1 cup of the whipped cream into a pastry bag and line the rim of the cake with whipped cream. Fill the middle of the cake with the halwa. Top with the remaining cake layer, then frost the entire cake with the remaining whipped cream. Garnish the cake with the pistachio dust, edible flowers and gold leaf. Slice and serve.