I no longer think that I’m the only one who benefits from my twice-weekly ab workouts.

While crunching away one morning in early December, a particularly stunning dessert was being made on America’s Test Kitchen, which, at the time, was my background diversion of choice. Naturally with kitchen equipment testings and step-by-step recipe guidance setting the tone for my workouts, these were no high-intensity affairs. Show host Christopher Kimball, who somehow manages to be irritating and interesting at the same time, was working with one of his Test Kitchen cooks on a Chocolate Dacquoise.

As I finished a set of alternating toe touches, the culinary duo was spritzing the meringue with water to prevent its top from drying out in the oven. I strained my neck watching them temper an egg mixture with warm milk during a set of particularly ineffective Russian twists. By the time Christopher and his partner set out to build this masterpiece, spreading one side of the meringue “bricks” with coffee buttercream and the other with dark chocolate ganache before laying one on top of another, I had abandoned the workout all together. Laying there flat on the floor, I realized this was the dessert I needed to make for Christmas dinner.

Lucky for me, I had my own partner in crime – my sister Lila – to help with this ambitious undertaking. We spent one evening making the hazelnut-infused meringue and sampling bits that broke of the finished product. The next night, we prepared the buttercream and chocolate ganache and made sure both were safe for human consumption. On the third day, we assembled our showstopper and helped ourselves to seconds along with the rest of our guests after a delicious Christmas dinner. On the fourth day, we delighted in leftovers and swore to work off the extra calories with a few more ab workouts…

Chocolate Dacquoise
Serves 10 to 12

Meringue
1/4 cup blanched sliced almonds, toasted
1/2 cup hazelnuts, toasted and skinned
1 tablespoon cornstarch
1/8 teaspoon salt
1 cup sugar
4 large egg whites, room temperature
1/4 teaspoon cream of tartar

Buttercream
3/4 cup whole milk
4 large egg yolks
1/3 cup sugar
1 1/2 teaspoons cornstarch
1/4 teaspoon salt
2 tablespoons Amaretto
1 1/2 tablespoons instant espresso powder (or instant coffee)
16 tablespoons unsalted butter, softened

Ganache
6 ounces bittersweet chocolate, chopped fine
3/4 cup heavy cream
2 teaspoons corn syrup

12 whole hazelnuts
1 cup blanched sliced almonds, toasted

1. FOR THE MERINGUE: Adjust oven rack to middle position and heat oven to 250°F. Using ruler and pencil, draw 13 by 10 1/2-inch rectangle on piece of parchment paper. Grease baking sheet and place parchment on it, ink side down.

2. Process almonds, hazelnuts, cornstarch, and salt in food processor until nuts ands finely ground, 15 to 20 seconds. Add 1/2 cup sugar and pulse to combine, 1 to 2 pulses.

3. Using stand mixer fitted with a whisk, whip egg whites and cream of tartar on medium-low speed until foamy, about 1 minute. Increase speed to medium-high and whip whites to soft, billowy mounds, about 1 minute. With mixer running at medium-high speed, slowly add remaining 1/2 cup sugar and continue to whip until glossy, stiff peaks form, 2 to 3 minutes. Fold nut mixture into egg whites in 2 batches. With offset spatula, spread meringue evenly into 13 by 10 1/2-inch rectangle on parchment, unsing lines on parchment as a guide. Using spray bottle, evenly mist surface of meringue with water until glistening. Bake for 1 1/2 hours. Turn off oven and allow meringue to cool in oven for 1 1/2 hours. (Do not open oven during baking and cooling.) Remove from oven and let cool to room temperature, about 10 minutes. (Cooled meringue can be kept at room temperature, tightly wrapped in plastic wrap, for up to 2 days.)

4. FOR THE BUTTERCREAM: Heat milk in small saucepan over medium heat until just simmering. Meanwhile, whisk yolks, sugar, cornstarch, and salt in a bowl until smooth. Remove milk from heat and, whisking constantly, add half of the milk to yolk mixture to temper. Whisking constantly, return tempered yolk mixture to remaining milk in saucepan. Return saucepan to medium heat and cook, whisking constantly, until mixture in bubbling and thickens to consistency of warm pudding, 3 to 5 minutes. Transfer pastry cream to a bowl. Cover and refrigerate until set, at least 2 hours or up to 24 hours. Before using, warm gently to room temperature in microwave at 50 percent power, stirring every 10 seconds.

5. Stir together amaretto and espresso powder; set aside. Using stand mixer fitted with paddle, beat butter at medium speed until smooth and light, 3 to 4 minutes. Add pastry cream in 3 batches, beating for 30 seconds after each addition. Add amaretto mixture and continue to beat until light and fluffy, about 5 minutes longer, scraping down bowl thoroughly halfway through mixing.

6. FOR THE GANACHE: Place chocolate in heatproof bowl. Bring cream and corn syrup to simmer in small saucepan over medium heat. Pour cream mixture over chocolate and let set stand for 1 minute. Stir mixture until smooth. Set aside to cool until chocolate mounds slightly when dripped from spoon, about 5 minutes.

7. TO ASSEMBLE: Carefully invert meringue and peel off parchment. Reinvert meringue and place on cutting board. Using serrated knife and gentle, repeated scoring motion, trim edges of meringue to form 12 by 10-inch rectangle. Discard trimmings. (Or snag a taste.) With long side of rectangle parallel to counter, use ruler to mark both long edges of meringue at 3-inch intervals. Using serrated knife, score surface of meringue by drawing knife toward you from mark on top edge to corresponding mark on bottom edge. Repeat scoring until meringue is fully cut through. Repeat until you have four 10 by 3-inch rectangles. (If meringues break during cutting, use them as middle layers.)

8. Place 3 rectangles on wire rack set in rimmed baking sheet. Using offset spatula, spread 1/4 cup ganache evenly over surface of each meringue. Refrigerate until ganache is firm, about 15 minutes. Set aside remaining ganache.

9. Using offset spatula, spread top of remaining rectangle with 1/2 cup buttercream; place on wire rack with ganache coated meringues. Invert 1 ganache-coated meringue, place on top of buttercream, and press gently to level. Repeat, spreading meringue with 1/2 cup buttercream and topping with inverted ganache-coated meringue. Spread top with buttercream. Invert final ganache-coated strip on top of the cake. Use 1 hand to steady top of cake and spread half of remaining buttercream to lightly coat sides of cake, then use remaining buttercream to coat top of cake. Smooth until cake resembles box. Refrigerate until buttercream is firm, about 2 hours. (Once buttercream is firm, assembled cake may be wrapped tightly in plastic and refrigerated for up to 2 days.)

10. Warm remaining ganache in heatproof bowl set over barely simmering water, stirring occasionally, until mixture is very fluid but not hot. Keeping assembled cake on wire rack, pour ganache over top of cake. Using offset spatula, spread ganache in thin, even layer over top of cake, letting excess flow down sides. Spread ganache over sides in thin layer.

11. Garnish top of cake with hazelnuts. Holding bottom of cake with 1 hand, gently press almonds onto sides with other hand. Chill on wire rack, uncovered, for at least 3 hours or up to 12 hours. Transfer to a platter. Cut into slices with sharp knife that has been dipped in hot water and wiped dry before each slice. Serve.

This recipe was originally published in the December 2012 issue of Cook’s Illustrated magazine.