Preheat oven to 160C fan-forced (180c non-fan). Unroll pastry, if the pastry is really cold to make it more pliable place your hands over the sheet of the pastry to warm it up. Line the base of a 22cm tart tin with baking paper. Use a 24cm dinner plate to cut a circle from the pastry. Line the tart tin with pastry, place in the fridge while you prepare the filling.
In a heat proof bowl that will fit snugly in a saucepan combine: dark chocolate, milk chocolate, sugar, maple syrup, vanilla and butter. Fill 1/3rd of a saucepan with water and bring to a simmer, place bowl on top ensuring the water does not come into contact with bowl. Stir until the chocolate and butter have melted and the sugar dissolved, remove from heat. Whisk eggs in a separate bowl. Add a spoonful of the melted chocolate mix to the eggs, whisk to combine, repeat with a second spoonful then return the egg mixture to the chocolate bowl and whisk to combine. Fold in the salted peanuts.
Pour filling into prepared tart shell, place on a baking tray and bake in pre-heated oven at 160c for 35 minutes or until tart just set.
Allow to cool for at least 1 hour before serving, then dust with cocoa powder and serve with crème fraiche or vanilla ice cream.