Beat yolks with sugar until creamy. Stir in lemon zest, 6 tablespoons mango puree and vanilla.
Whip the cream until stiff and fold in carefully.
Pour the parfait mixture into small ramekins or a loaf pan and freeze for about 4-6 hours.
Remove from the freezer a few minutes before serving, invert the molds and serve with the remaining mango puree and chopped pistachios.