1. 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.

2. Preheat the oven to 350°F.

3. 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.

4. 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.

5. Prepare the ganache filling: Place the chocolate in a medium-size bowl, and set it aside.

6. 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.

7. 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.

8. Cut the tart into thin wedges and serve, with the crème fraîche alongside.