Looking for a dazzling dessert? Pair chocolate decadence with stunning looks, like this tart does, and you’ve got one. It ends many of our special-occasion meals and will do so again this Valentine’s Day.

The filling is what makes it memorable. White chocolate, enlivened with a little sour cream, is swirled through dark, bittersweet chocolate, creating delightful contrasts in color and taste as well as a texture as smooth as velvet. I like to cradle the striking filling in a dark chocolate pastry shell. However, you can substitute any crust you like. Just be sure to blind bake it because the filling requires no time in the oven, so the crust must be fully baked before it’s filled.

Swirled Chocolate Tart

Make in a 9-inch tart pan with a removable bottom. Works at any elevation.

Chocolate Crust (optional)

• 1 1/4 cups all-purpose flour
• 1/4 cup granulated sugar, preferably superfine
• 1/4 cup unsweetened cocoa powder
• 1/4 teaspoon salt
• 8 tablespoons unsalted butter (one stick), cold
• 1 large egg yolk
• 1 tablespoon ice water

Place the flour, sugar, cocoa powder and salt in the bowl of a food processor and pulse until combined. Cut the butter into 16 pieces, add them, and pulse until the dough looks like coarse meal and there are clumps the size of small peas. With the motor running, add the egg yolk and ice water, and pulse until the dough is fully moistened but still crumbly. If necessary, add another teaspoon of ice water. Turn the dough out onto a sheet of waxed paper or plastic wrap, and knead it a few times to bring it together. Form it into a disc, wrap and refrigerate until it’s firm.

Preheat the oven to 350 degrees. Lightly grease the bottom of the tart pan. Roll the dough to a circle about 11 inches in diameter, gently fit it into the tart pan, trim the top and freeze until firm. Line the crust with nonstick or greased foil (nonstick side on the crust), fill with pie weights, place on a cookie sheet and bake until the crust is set, about 18 minutes. Remove it from the oven, take out the weights and foil and return the crust to the oven to bake until dry and firm, an additional 7-11 minutes. Don’t overbake the crust or it will taste bitter. Cool and set aside.

Filling

• 6 ounces high-quality bittersweet chocolate (not over 61% cacao)
• 2/3 cup heavy cream
• 2 large egg yolks
• 2 tablespoons dark rum
• 6 ounces high-quality white chocolate
• 1/2 cup sour cream (don’t use nonfat)

Finely chop the bittersweet chocolate and set it aside. In a big, deep skillet, heat about an inch of water to a simmer. Whisk the cream and egg yolks in a heatproof bowl until combined. Then, place the bowl in the simmering water and continue whisking until the mixture thickens and registers 160 degrees on a kitchen thermometer. Heating the egg yolks to this temperature is a safeguard against salmonella. Remove the bowl from the pan, add the chopped chocolate and stir until smooth. Add the rum and stir until smooth again. Set this aside. If you have a double boiler, use it in place of the skillet of simmering water.

Chop the white chocolate into fine pieces, place it in a second heatproof bowl and move it to the simmering water. Stir constantly until it’s almost fully melted. White chocolate overheats easily, which makes it grainy, so make sure the water is at a slow simmer, keep the chocolate moving around in the bowl, and remove it from the water while some of the chocolate is still in small lumps. After removing it from the water, stir until it melts completely, add the sour cream and stir until it’s smooth. Let both chocolate mixtures cool until they are slightly warmer than room temperature.

To assemble the tart, spoon the chocolate mixtures into the cooled tart shell, alternating their placement. Gently shake the pan to settle the chocolates, then draw the back of a knife or a skewer through them, creating swirls. Refrigerate the tart, loosely covered, for at least 9 hours until it is set before cutting and serving it. Slice it with a thin, sharp knife, wiping it clean between cuts. A drizzle of raspberry sauce is a lovely, but optional, accompaniment.

Editor’s note: The crust recipe is a variation of one published in “Baking with Julia.” The filling recipe is a variation of one published by Gourmet Magazine.

Vera Dawson’s column “High Country Baking” publishes biweekly at SummitDaily.com. Dawson is a high-elevation baking instructor and author of three high-altitude cookbooks. Her recipes have been tested in her kitchen in Frisco, where she’s lived since 1991, and altered until they work at elevation. Contact her at veradawson1@gmail.com.

Vera Dawson’s column “High Country Baking” publishes biweekly in the Summit Daily News. Dawson is a high-elevation baking instructor and author of three high-altitude cookbooks. Her recipes have been tested in her kitchen in Frisco, where she’s lived since 1991, and altered until they work at elevation. Contact her at veradawson1@gmail.com.