Heat ghee in a heavy-bottomed kadai on low heat.
Add desiccated coconut. Roast over low heat for 2-3 minutes or until it gives out a nutty aroma.
Add milk and cream. Cook, stirring continuously until the milk is absorbed by the coconut.
Add sugar and mix well, the sugar will melt and release moisture.
Cook, stirring continuously until the most of the moisture evaporates.
Add milk powder, mix and cook until the mixture comes together, forms a dough-like consistency, and starts leaving the sides of the kadai.
Add cardamom powder, and give it a good mix.
To check if the mixture is done, take a small portion of the mixture and check if you can form a ball. If you can, then it's ready. If not, cook for a few more minutes.
Switch off the heat, and transfer the mixture to the prepared tray.
Press it down with the help of a spatula. Make sure you pack it firmly.
Sprinkle slivered pistachios and edible dried rose petals. Press it gently using a spatula.
Set the coconut barfi for 3 to 4 hours or overnight in the fridge.
Cut the set coconut burfi into desired-sized pieces.