In a nonstick pot, heat 2 cups of whole milk over medium heat until it boils, about 5 minutes. Add a pinch of saffron and simmer for another 5 minutes. Stir in chopped almonds and cashews, followed by the sugar. Boil for another 10 minutes, mixing occasionally until the mixture thickens. Add ground cardamom and cook until reduced by half. Transfer to a bowl and let cool for 30 minutes before refrigerating for at least 1 hour.

Chill your mixing bowl in the fridge for 30 minutes. Pour in the cold heavy whipping cream and beat with a hand mixer at medium speed for 2-4 minutes until stiff peaks form.

Once cooled, gently fold in 1/2 cup of the ras malai liquid into the whipped cream using a spatula. Gradually fold in the remaining ras malai liquid until completely combined. Taste and adjust sweetness if needed.

Spoon the mousse into glasses, filling them three-quarters full. Cover with plastic wrap and chill for several hours. Garnish with rose petals, saffron, and chopped pistachios before serving.