1) Heat oven 325 degrees.
2) Place chocolate in a medium sized bowl. Bring 1/2 cup of cream, almost to a boil. Pour over chocolate, and stir until smooth.
3) In a separate bowl, whisk together eggs and sugar until smooth.
4) Add to the chocolate mixture, mixing well. Set aside.
5) In a saucepan, heat remaining cream, milk and passionfruit concentrate. Bring almost to a boil.
6) Whisk milk mixture, to egg mixture, in a stream until blended. Skim off any froth. Divide evenly between ramekins.
7) Set ramekins in a deep pan. Fill pan with hot water, coming up about 1/2 way up the side of the ramekins.
8) Bake in the middle of the oven until just set, but trembles slightly. About 35-40 minutes.
9) Remove from pans and chill.
10) Just before serving sprinkle tops of custard with raw sugar.
11) Place under broiler on high until sugar is hot and bubbly. About 2-3 minutes.