FOR THE CHOCOLATE PASTRY:
- 1 large egg yolk
- 3 tbsp heavy cream
- 1 tsp pure vanilla extract
- 1 1/4 cups all-purpose flour
- 1/4 cup cocoa powder
- 1/2 cup granulated sugar
- 1/4 cup dark brown sugar
- 3/4 tsp salt
- 10 tbsp salted butter, cut into 1/2-inch pieces
FOR THE TRUFFLE FILLING:
- 18 oz good quality bittersweet chocolate
- 9 tbsp salted butter, at room temperature, cut into 1/2 inch pieces
- 1 1/2 cups heavy cream
- 1/2 tsp salt
- 2–4 tbsp Grand Marnier (to taste)
MAKE THE PASTRY:
- Whisk the egg yolk, cream and vanilla together in a small bowl.
- Add the flour, cocoa powder, both sugars, and salt to the bowl of a food processor fitted with the dough (pastry) blade. Pulse a few times to combine.
- Scatter the pieces of butter over the flour mixture and pulse about 10 times – until the mixture resembles coarse cornmeal.
- With the machine running, pour in the egg and cream mixture all at once. Continue to pulse just until the mixture begins to comes together into a dough. Be careful not to over mix.
- Dump the dough onto a clean work surface and knead a few times, just to ensure all the dry ingredients are incorporated. Pat into a disc, wrap tightly in plastic wrap, and refrigerate for 30 minutes, and up to 2 days.
- After the dough has had time to chill, roll it out on a floured work-surface and gently lift into an 11-inch tart pan with a removable bottom. Press the dough into the sides and corners of the pan, allowing excess dough to fold over the edge of the pan. Use a rolling pin to roll over the edges of the pan, cutting off the excess dough. Cover and freeze for at least 30 minutes, and up to 2 weeks.
- Preheat the oven to 375 degrees. Remove the pastry from the freezer and line with foil. Fill the foil-lined pastry with dried beans or pie weights and bake for 30 minutes. Carefully remove foil and beans or pie weights from the pastry shell and bake for 5-10 minutes longer.
- Remove the crust from the oven to a wire rack and allow to cool completely before filling.
MAKE THE TRUFFLE TART FILLING:
- Add the chocolate and butter pieces to a large bowl.
- Heat the cream to boiling either on the stovetop or in the microwave.
- Pour the cream over the butter and chocolate and allow to sit for 5 minutes. Stir the ganache until completely smooth. If, after stirring for a few minutes, there are pieces of chocolate or butter that have not yet melted, microwave the mixture in 30 second increments at half power until the ganache is completely smooth. Stir in the salt and Grand Marnier to taste.
- Pour the truffle tart filling into the cooled pastry and refrigerate until firm – at least two hours.
- If desired, top with candied orange peel. Serve chilled or at room temperature.