Finely chop the chocolate and put it into a large heatproof bowl. Scald the cream by bringing it to the boil. Add the tea and leave to stand for 2 minutes; strain.
Pour the cream bit by bit on to the chocolate. Use a rubber spatula to stir it in, ensuring a smooth emulsion. (If it gets too cool to melt the chocolate, you may have to heat it gently again.) Add the orange flower water.