1/4cup plus 1 tablespoon dutch-process unsweetened cocoa powder
1/4teaspoon kosher salt
10tablespoons unsalted butter, cubed and softened
1/2cup plus 2 tablespoons confectioners' sugar
2-- egg yolks, preferably at room temperature
1/2teaspoon vanilla extract
1 1/2cups sugar
3tablespoons light corn syrup or Lyle's golden syrup or brown rice syrup
1/4teaspoon kosker salt
6tablespoons unsalted butter
6tablespoons heavy cream
1tablespoon crème fraîche
1/2cup heavy cream
4ounces bittersweet chocolate, finely chopped
-- Sea salt for garnish
Preheat oven to 350F.
To make the crust: Combine flour, cocoa powder and salt in a medium bowl and set aside. Using a handheld mixer, cream the butter and sugar in a large bowl until mixture is pale and fluffy; mix in yolks and vanilla. Mix in dry ingredients. Transfer dough to a 9-inch fluted tart pan with a removable bottom and press dough evenly into bottom and sides of pan. Refrigerate 30 minutes. Prick tart shell all over with a fork and bake until cooked through, about 20 minutes. Transfer to a rack and let cool.
To make the caramel filling: In a 1-quart saucepan, whisk together sugar, corn syrup, salt, and 6 tablespoons water and bring to a boil. Cook, without stirring, until a candy thermometer inserted into the syrup reads 340F. Remove pan from heat and whisk in butter, cream and crème fraîche (the mixture will bubble up) until smooth. Pour caramel into cooled tart shell and let cool slightly; refrigerate until firm, 4 to 5 hours.
To make the ganache: Bring cream to a boil in a 1-quart saucepan over medium heat. Put chocolate into a medium bowl and pour in hot cream; let sit for 1 minute, then stir slowly with a rubber spatula until smooth. Pour ganache evenly over tart and refrigerate until set, 4 to 5 hours. Sprinkle tart with sea salt.
Adapted by Rachel Willen, Food Fixme.com, from Marlow & Sons Restaurant, N.Y., via The New Comfort Food, edited by James Oseland.