In the saucepan, bring the heavy cream and the tea to the boiling point. Cover up with plastic wrap and leave it to cool down for 15 minutes.
Strain, then weigh it. Make sure to have the same amount as in the beginning, then bring it to the boiling point one more time. Add lemon zest or orange zest.
Add the white chocolate and blend everything together until fully combined.
Slowly incorporate the cold heavy cream while blending.
Cover with plastic wrap and leave it in the fridge for 12 hours.