Add 1 and ½ liters of whole milk (full-fat milk) and a pinch of saffron strands to a non-stick heavy-bottomed and wide pan.
Once the milk is thick and creamy, add ¼ cup sugar, ½ teaspoon ground cardamom and ¼ cup slivered nuts to the pan and cook for 3-4 minutes until the sugar is dissolved.
Cool until the basundi comes to room temperature. Stir in 1 cup of mango puree and chill the mango basundi for 3-4 hours. Transfer the basundi to serving cups or bowls and garnish with chopped mangoes, more slivered nuts, and dry rose petals.
Mango Basundi is ready!