- 8 tablespoons (1 stick) unsalted butter, chilled, cut into cubes
- ½ cup confectioners sugar
- ½ cup almond flour (see Note)
- 1/3 cup plus 1¼ cups all-purpose flour
- 1 large egg, lightly beaten
- ½ teaspoon pure vanilla extract
- ½ teaspoon salt
- 12 ounces good-quality bittersweet or semisweet chocolate, chopped (chips or pastilles can be used)
- 1¼ cups heavy whipping cream
- 1 tablespoon light corn syrup
- 1 tablespoon unsalted butter
- 8 ounces creme fraiche
- Prepare the tart crust: Using an electric mixer, beat the butter, confectioners’ sugar, almond flour, the 1/3 cup all-purpose flour, and the egg and vanilla in a bowl, scraping down the sides of the bowl as needed, until well combined, about 2 minutes. Add the remaining 1¼ cups flour and the salt, and mix until just blended. Form the dough into a thick disk. Wrap it in plastic wrap and refrigerate it for at least 2 hours or as long as 2 days. Or, for faster chilling, place the wrapped dough in the freezer for 30 minutes.
- Preheat the oven to 350°F.
- Remove the dough from the refrigerator and roll it out on a lightly floured work surface to form an 11-inch round, about ¼ inch thick. Fit the dough into a 9-inch tart pan with a removable bottom, and trim off the overhang.
- Bake the tart crust until it is golden brown, about 15 minutes. Place the pan on a wire rack and allow the crust to cool. When the crust is cool enough to handle, carefully remove it from the sides of the pan and place the crust on a decorative plate. Set it aside.
- Prepare the ganache filling: Place the chocolate in a medium-size bowl, and set it aside.
- Combine the cream; corn syrup, and butter in a saucepan over medium heat and bring just to a boil, stirring to combine. Immediately pour this over the reserved chocolate, and cover the bowl with plastic wrap. Let it stand for 1 minute, and then stir to combine. Re-cover the bowl, let it stand for 1 minute longer, and then stir again. Set the ganache aside to cool for about 15 minutes.
- Pour the ganache mixture into the tart crust. Let it sit at room temperature until it is thickened and set, 2 to 4 hours; or chill it in the refrigerator for 2 hours.
- Cut the tart into thin wedges and serve, with the crème fraîche alongside.