Grease an 8-inch square baking pan or brownie tin.
Melt the chocolate and butter in a large stainless steel bowl placed over a saucepan of simmering water. Remove from heat and stir in the sugar.
Next, whisk in the vanilla extract and eggs, one at a time, beating well after each addition.
Finally, stir in the flour and salt. Pour into the prepared pan and bake for about 25 minutes, or until a toothpick inserted in the centre comes out with a few moist crumbs.
Remove from oven and let cool on a wire rack.
For the Chocolate Ganache:
Place the chopped chocolate in a medium sized stainless steel bowl. Heat the cream and butter in a small saucepan over medium heat.
Bring just to the boil and immediately pour the boiling cream over the chocolate and allow to stand for 5 minutes. Stir with a whisk or spoon until smooth.
For the Iced Mint Crème Fraiche:
Blanch the mint leaves in hot water for 30 seconds in a bowl and then immerse in iced water. Blitz them in a food processor.
To make the ice cream, split the vanilla pod in half and scoop the seeds into a pot along with the pod, the milk and the cream. Bring everything to just under the boil.
Whisk the egg yolks and sugar until pale and thick. Pour the hot cream and milk mix over them, whisking all the time.
Sieve this mixture back into the pot and cook on a low heat until the mixture coats the back of a spoon, stirring constantly.
Remove from the heat and add the blitzed mint leaves, crème fraiche (and the Crème de Menthe and green food colouring, if using) until fully combined. Churn in an ice cream machine until thick.
To Assemble: Using a scone cutter, cut a round from the pudding tin and place on your plate or bowl. Pour over the warm chocolate ganache and a scoop of ice cream and serve immediately. If you like, you can drizzle some melted white chocolate over the top before serving.