Recipe: Bittersweet Chocolate Tart with Raspberry Dust

This tart recipe is based on one made by renowned French chef Joël Robuchon. It’s simple to make, deeply bittersweet and quite rich.  The berry “dust” is an optional addition and gives the tart a modern edge — “dust” is popular in molecular gastronomy dishes and is made from dehydrated ingredients, pulverized. Garnishing dishes with “dust” is a simple way to zip up your cooking and surprise your guests.  The tart shell includes almonds, but skinned hazelnuts could be substituted.

MAKES ONE 9-INCH TART

PASTRY SHELL

1 plump vanilla bean

1 large egg yolk, at room temperature
1/2 cup confectioner’s sugar, sifted

2 -3 tablespoons slivered or blanched, sliced almonds
¾ cup all-purpose flour, sifted
Pinch of salt
5 tablespoons unsalted butter, at room temperature

Filling
3/4 cup heavy cream
1/3 cup milk
7 ounces imported bittersweet chocolate*, grated or finely chopped (I use Valrhona or Callebaut)
1 large egg, lightly beaten

* make sure not to use extra-bittersweet chocolate, since the tart has no added sugar and this would create an under-sweetened result

Optional: berry dust and fresh raspberries as garnish (see instructions below)

MAKE THE PASTRY SHELL:

1. Flatten the vanilla bean and cut it in half lengthwise. With a small spoon, scrape the seeds into a small bowl. Add the egg yolk and stir to blend.

2. In a food processor, combine the sugar and almonds and process until the nuts are finely ground. Add the flour and salt and process to blend. Add the butter and process just until the mixture resembles coarse crumbs.  Add the egg yolk mixture and pulse until the dough holds together. It’s okay if it forms a ball (I view this as sort of kneading the dough). Use a 9-inch fluted tart pan with a removable bottom. An option is to cut a piece of parchment paper the size of the bottom of the pan in order to be able to remove the tart from the pan easily before serving.

3. Make little “snakes” of dough with your fingers and press them around the sides of the tart pan, forming the right shape and thickness.  Your fingers will work fine to shape and flatten the top of the sides.  Spread the remaining dough across the bottom, using your fingers to make everything even. Freeze it until ready to bake. (The original recipe had a painstaking process of rolling out the dough, which I never do for tart dough.)  Refrigerate until well chilled, at least 1 hour. Or freeze for up to a week.

4. Preheat the oven to 375° (convection bake if possible). Prick the chilled or frozen dough all over with a fork. Set the tart pan on a cookie sheet. I recommend putting a large piece of parchment paper filled with pie weights or dried beans into the bottom. (If you use waxed paper, it will remove some of the tart dough when removed, so it isn’t optimal.)  Bake for 10 minutes, then remove from oven and carefully remove the parchment and weights.  Return to oven and bake another 10 minutes, until it’s a bit golden.  If the top edges seem to be getting too brown after the first 10 minutes (quite likely), crimp narrow strips of aluminum foil over them. Transfer to a rack and let cool before filling.  Remove the strips of foil before adding filling.

Make the filling:

1. In a medium saucepan, bring the cream and milk to a simmer. Remove from the heat. Add the chocolate; stir until melted. Let cool to lukewarm and then whisk in the egg until thoroughly blended.

2. Pour the custard in the pastry shell; bake in the middle of the oven for 12 to 15 minutes, or until the filling is almost set but still trembling in the center. Transfer to a wire rack to cool. If you don’t want to include the berry dust, consider serving the tart a little warm, which enhances the chocolate richness.

MAKING BERRY DUST

Freeze-dried raspberries and strawberries are available at Whole Foods, Trader Joe’s and possibly other places.  They are not sweetened before being dried.  Trader Joes has blueberries, raspberries and divine strawberries.  Whole Foods has these three, as well as peaches, cherries, pears, pineapple, apples, mangoes, bananas, peas, tomatoes, corn — possibly more items as well.  Raspberries are optimal for the chocolate tart.

The trick of the berry dust is to make it right before garnishing the tart.  If you make it and let it sit, it will clump up and you’ll need to press it through a fine sieve to “re-dust” it.  Believe me, this is a big pain. Making the dust is simple: Put the berries in a blender (recommended option: add a little sugar) and blend until they’re pulverized.  For the raspberries, I also ran the dust through a fine sieve to remove the small seeds afterward.  As you’ll see in the photos, the berry dust on top of the tart is in a design.  I bought stencils at a crafts store to do this.  (To be specific: Jo-Ann Fabrics & Crafts in Los Altos.)  However, you can simply dust the whole top of the tart, use a paper doily or other object as a stencil , or make designs by hand if you’re artistic.  Important: If using stencils of any kind, the tart must be room temperature or the stencil will stick to the filling.

Other options are to sprinkle berry dust around the outside of the tart as additional garnish and add fresh raspberries around the edges of the tart (do this AFTER applying the dust) as seen in the photo. The raspberries aren’t sweetened or glazed, but they can be if you’re so inclined.