Peel and puree the ripe mangoes until smooth.
Pour full-fat milk into a heavy-bottomed pan and simmer until slightly reduced.
Add condensed milk and sugar, then stir well.
Add cardamom powder and mix thoroughly.
Allow the milk mixture to cool completely, then mix in the mango puree.
Pour the mixture into kulfi molds and freeze for at least 6 hours or overnight.
Remove from the molds, garnish with chopped pistachios or mango pieces, and serve chilled.