Pour full-fat milk into a heavy-bottomed pan and bring it to a gentle boil.
Simmer on low heat, stirring regularly, until the milk reduces and becomes creamy.
Add sugar, rose syrup, and cardamom powder. Mix well.
Add chopped pistachios and almonds, then cook for another 2–3 minutes.
Allow the mixture to cool completely.
Pour into kulfi molds and freeze for at least 6 hours or overnight.
Remove from the molds, garnish with rose petals and chopped pistachios, and serve chilled.