Chocolate Caramel Tart

1. Make the Tart Dough

Cream together the salted butter, confectioners' sugar, and unsweetened cocoa with an electric mixer until smooth. Add the large egg yolk and vanilla extract, continuing to beat until well-blended. Sift in the all-purpose flour, and beat the dough until just combined. Press the dough into a 10-inch tart pan, forming a shell.

2. Blind Bake the Crust

Pre-bake the crust by pressing a piece of foil against the dough, filling it with dried beans, rice, or pie weights. Bake for 15 minutes, then remove the weights and foil and bake for another 10-15 minutes until the pastry is dry and set.

3. Prepare the Caramel

In a large saucepan, combine the sugar, water, and corn syrup. Boil without stirring until it reaches a medium amber color, about 12 minutes. Then quickly whisk in the unsalted butter, heavy cream, crème fraîche, and a pinch of salt after removing from heat. Pour the caramel into the tart shell and let it set for at least an hour.

4. Make the Chocolate Glaze

Melt the extra-bittersweet chocolate with the remaining heavy cream in a bowl set over simmering water, stirring until smooth and glossy. Pour the glaze over the set caramel and tilt the tart for an even layer. Sprinkle fleur de sel over the glaze and let the tart set in the refrigerator for at least one hour before serving.