This was my second try with this tart. The first time I made it, I used buckwheat flour only in the crust, and it crumbled. It was still tasty, but certainly not presentable. So the second time, I decreased the buckwheat to regular flour ratio 1:3, and it worked much better. There is still the taste of lovely, nutty buckwheat, AND you can slice it without the tart falling apart. Once you make this tart, you’ll see it disappear very quickly…it is very rich in chocolate flavor, without being too heavy. Enjoy!
For the crust
8 tablespoons (4 ounces) unsalted butter, melted
1 tbsp. sugar
1/8 teaspoon salt
3/4 teaspoon vanilla extract
1/4 cup buckwheat flour
3/4 cup all-purpose flour
For the filling
3 tablespoons unsalted butter, cut into chunks
1/3 cup sugar
1/4 cup good quality unsweetened cocoa powder (natural or Dutch-process)
1 cup heavy cream
1 1/4 teaspoons instant espresso powder (such as Medaglia d’Oro), or 1 1/2 teaspoons instant coffee crystals
1/2 teaspoon pure vanilla extract
1 large egg, lightly beaten
Make the crust
Position a rack in the lower third of the oven and preheat the oven to 350°F (175°C).
Mix the butter, sugar, salt, and vanilla in a medium bowl. Add the flour and mix just until well blended. Don’t worry if the dough seems too soft. Press all of the dough very thinly and evenly into the bottom and up the sides of a 9 inch removable bottom tart pan. Bake for 20 to 25 minutes or until the crust is a deep golden brown.
Make the filling
Place the butter, sugar, cocoa powder, and cream in a medium saucepan and cook over medium heat, whisking, until the mixture is blended and smooth and begins to simmer around the edges. Remove from the heat and stir in the coffee powder and vanilla.
Just before the crust is ready, whisk the egg thoroughly into the hot chocolate mixture.
Pour the filling into the hot crust and turn off the oven. Leave the tart in the oven until it quivers like tender Jell-O in the center when the pan is nudged, about 10 to 12 minutes. Cool on a rack then in the fridge for at least four hours.
Recipe adapted from leitesculinaria.com