Preheat oven to 180C

Spray a 23cm tart tin with non stick cooking spray.

Using a floured rolling pic, roll the pastry out until its big enough to line the 23cm tart shell tin without stretching and with at least 2cm overhang all the way round. Lifting the pastry carefully gently line the inside of the tart tin, leaving the excess hanging over the rim. Using a fork prick the pastry at the bottom of the tart tin a few times. This will stop if from rising.

Place baking paper that you have scrunched up a little to make it easier to handle inside the tart and fill with dried split peas, chickpeas or pastry weights. Place in the oven and cook for approx 10mins until the edges start to become golden.

At this stage remove from the oven and remove the paper and weights and push down on the tart tin edge, breaking off the excess pastry. Return to the oven and continue to back for another 10 minutes until its golden brown. Place aside to cool completely. Reduce the oven temperature to 110C.

In a saucepan add the cream, milk and sugar and heat over medium heat until just below boiling point. The surface will have lots of small bubbles appear and begin to look like foam. Remove from heat and add the chocolate and stir until completely melted in with the cream mixture.

In a small bowl beat the eggs, vanilla essence and salt until well mixed and the eggs is fluid. Add a little of the hot chocolate mixture to the egg mixture and mix to combine. Now pour the egg mixture into the rest of the chocolate mixture and stir well to combine.

Using an extra fine strainer, strain the chocolate mixture into the tart shell.

Place the filled tart shell back into the oven and bake for approx 40mins until set. When cooked remove from the oven. The surface should be set but still a little wobbly in the centre. If it starts to bubble or crack remove from the oven as its starting to overcook. 

Allow to cool for two hours before serving. Before serving dust with cocoa powder.