- With the rack in the middle position, preheat the oven to 350°F (180°C).
- In a bowl, combine all of the ingredients. Press the crust into the bottom and up the sides of a 9-inch (23 cm) tart pan with removeable bottom or glass pie dish. Bake for 15 minutes. Let cool.
- Zest the oranges. Remove the peel down to the flesh, then slice the flesh into rounds. Set the orange slices aside in a bowl until ready to serve.
- Place the chocolate in another bowl.
- In a pot off the heat, whisk together the cream, milk, sugar, egg yolks and orange zest. Cook over medium-low heat, stirring constantly, until the cream has thickened slightly. Pour over the chocolate and let sit for 2 minutes without stirring. Whisk until smooth.
- Pour the chocolate cream into the cooled crust. Refrigerate for 3 hours or until the filling has set.
- Using a fine grater, sprinkle dark chocolate shavings over the top of the tart. Add a pinch of Maldon salt and garnish with the reserved orange slices. The tart will keep for 3 days in the refrigerator.
Maldon salt is a great option for garnishing desserts since the crystals are more delicate than other fleurs de sel on the market.