Place the flour, cocoa, sugar and salt in the bowl of a food processor, pulse several times to combine Add the butter and pulse until the mixture resembles coarse meal, about 10 seconds Add the egg yolks and vanilla and process just until the mixture begins to hold together, no more than 30 seconds Turn dough out onto a lightly floured surface and form a disk.
Cover in plastic wrap, refrigerate for 30 minutes or until ready to use.
For the Tart----------------.
Preheat the oven to 350F degrees.
Roll the chocolate pate sucree to 1/8" thick and fit into a 9" fluted tart pan with a removable bottom Dock the bottom of the tart with a fork.
Refrigerate the shell for 30 minutes.
Place chopped pecans on a baking sheet and toast until slightly darkened and fragrant, about 10 minutes, set aside.
Line tart shell with parchment paper, pressing into edges and cover with dried beans or pastry weights.
Place on a baking sheet, bake for 20 minutes.
Remove paper and beans, continue baking until crust is golden, about 10 minutes.
Transfer to a wire rack and cool completely.
Make the caramel by placing the sugar, salt and water in a small saucepan.
Bring the mixture to a boil over medium high heat.
Wash down the sides of the pan with a wet pastry brush to prevent crystals from forming.
Cook, gently swirling (do not stir) until the caramel is a rich amber color.
Remove from heat and add 1/2 c of cream, butter and vanilla.
Stir until smooth.
Pour mixture into chocolate tart shell.
Sprinkle with toasted pecans and place in the refrigerator while melting the chocolate.
Place chocolate in a medium heat-proof bowl.
Bring remaining cup of cream to a boil in a small saucepan.
Pour over the chocolate, let sit for 5 minutes.
Stir until completely smooth.
Pour over caramel and pecans.
Return tart to refrigerator and chill for at least 1 hour.
To serve, dust the op with cocoa powder and garnish with Caramel-Dipped Pecans For Caramel-Dipped Pecans-----------------.
Gently insert an 8" wooden skewer into each pecan, set aside.
Prepare an ice bath, and set aside.
Combine the sugar, water and cream of tartar in a medium saucepan and bring to a boil over medium-high heat Wash down the sides with a wet pastry brush to stop crystals from forming.
Cook, without stirring until the mixture begins to brown.
Gently swirl the pan to color evenly.
Remove from heat when the caramel is a rich amber color, place the pan in an ice bath to stop the caramel from cooking, about 5 seconds.
Allow the caramel to sit, until slightly thickened for about 15 minutes.
When caramel is ready, dip pecans, lifting up and swirling slightly to fully coat.
Hold skewer over pan to allow the drip to lengthen and slightly harden, about 1 minute.
Place the skewers in a cube of flower foam to stand them upright, allow to completely harden.