2) Place half of the cream, the milk, sugar and remaining butter into a saucepan set over a medium heat.
3) Add the vanilla, and salt and bring to a simmer.
4) Put the chocolate into a medium bowl and pour in the cream mixture. Let sit for about 5 minutes, until the chocolate is melted.
5) Add the eggs and mix until well combined.
6) Line the baking dish with the bread slices, overlapping slightly. Pour the chocolate mixture over the bread, making sure to cover the tips. Push the bread down with your fingers to coat the bread completely. Cover and refrigerate for at least 2 hours. Remove from the refrigerator 30 minutes before baking.
7) Preheat the oven to 180C/gas 4.
8) Bake for about 30 minutes, until the custard sets and the bread turns golden at the edges.
9) Pour the remaining cream into a chilled bowl and whisk until soft peaks form. Serve the French toast on individual plates with a dollop of cream.