Orange Chocolate Tart

To prepare candied orange peel: Remove 1 teaspoon zest from a small area of the orange with a zesting tool; set aside for the crust (Step 5). Use a vegetable peeler to remove the rest of the orange peel in long strips from top to bottom. Slice the strips into thinner long strips.

Combine the strips and 2 cups water in a medium saucepan. Boil over high heat for 10 minutes. Drain in a fine-mesh sieve. Return the strips to the pan, add 2 cups water and boil for 10 minutes more. Drain again, leaving the strips in the sieve.

Combine the remaining 1 cup water, 1 cup granulated sugar and cinnamon stick in the pan. Bring to a low boil, stirring to dissolve the sugar. Add the orange peel strips. Reduce heat to a gentle simmer and cook until the peels are very soft, 20 to 30 minutes. Drain the syrup into a container and set aside for the filling (Step 9).

Transfer the peels to a small bowl and toss with the remaining 3 tablespoons sugar until coated. Use a fork to transfer them to a parchment-lined tray. If desired, twist peels around toothpicks to make corkscrew shapes. Let stand until dry, about 2 hours.

To prepare crust: Sift together flour, cocoa and cinnamon in a small bowl. Beat butter, confectioners' sugar, orange zest and salt in a mixing bowl with an electric mixer until very creamy, scraping down the sides halfway through. Add egg and vanilla and beat until well combined. Scrape down the sides and beat for 30 seconds more. Add the flour mixture and mix on low speed just until incorporated. Scrape the dough onto a piece of plastic wrap, shape into a 1/2-inch-thick disk, tightly wrap and refrigerate for at least 1 hour and up to 3 days. (The dough will be very soft.)

When ready to assemble tart: Roll out the dough between sheets of parchment paper into a 12- to 13-inch circle. Remove the top sheet and invert the dough into an 11-inch tart pan, lining the bottom and sides. Trim off any extra overhanging dough and use to patch any thin spots. Prick the dough all over with a fork and freeze for 1 hour.

Preheat oven to 350 degrees F.

Bake the crust until it looks dry and is pulling away from the edges of the pan, about 20 minutes.

To prepare filling: Put chocolate in a medium bowl. Whisk milk, cream, 1/4 cup of the reserved orange syrup and cornstarch in a small saucepan until combined. (Reserve the remaining syrup for another use.) Bring to a boil over medium heat, whisking occasionally. Boil, whisking constantly, for 1 minute. Pour the mixture over the chocolate. Add orange extract, vanilla and salt and stir until the chocolate is melted. Pour into the crust and smooth the top.

Refrigerate the tart until very cold, at least 4 hours. Serve topped with the candied orange peel.