Preheat the oven 350 F. Grease a 8X8 pan with oil/melted butter and line with parchment paper. The parchment paper should hang on all the four sides.
In a food processor, pulse the flour, orange zest, sugar and salt until everything is mix; around ~5 pulses.
Add the butter and vanilla and pulse until the mixture looks fine and crumbly.
Transfer the shortbread-crust mixture to the prepared pan and gently pat it down into an even layer, using your hands or a flat bottom cup.
Using a fork, poke holes across the surface.
Refrigerate the crust for 30 minutes.
Bake the crust for 20 minutes, the shortbread should be barely golden brown.
Remove the pan from the oven and let the crust cool to room temperature on wire rack.
Gajjar Halwa filling
Preheat the oven to 400 F. Make sure the above shortbread crust has cooled down to room temperature.
In a medium sauce pan on a medium add ghee and carrots, cook for a minute.
Stir in evaporated milk and pinch of salt, bring the mix to a gentle boil. Reduce to heat to low and let the carrots cook for 10 minutes.
Turn off the heat, add caradamom, sugar and cornstarch to the carrot mix. Give everything a nice stir and blend it to a smooth mix in a high speed blender.
Pour the filling in prepared pan, bake for 20 to 30 minutes. The center of the pan should not be jiggly.
Remove the pan from oven, garnish with dried nuts and rose petals and let it cool down to room temperature.
Refrigerate the pan for at least 2 hrs before cutting them into square pieces.
Store the bars in fridge, serve it cold or at room temperature.