Recipe Detail Page

1 Set oven racks in the upper and lower middle positions and preheat oven to 350°F (180°C).

2 Butter and flour the bottom and sides of two 6-inch (15-cm) square pans, two 6-inch (15-cm) round pans, and one 8-inch (20-cm) round cake pan. Line the bottom of each with parchment paper.

3 Place chopped chocolate in a medium bowl. Pour in the boiling water and gently whisk until the chocolate is melted and smooth. Cool to room temperature.

4 Sift together the flour, baking powder, baking soda and salt and set aside.

5 Cream the butter in an electric mixer fitted with the paddle attachment. Gradually add the sugar and beat on medium speed for about 5 minutes, until pale and fluffy, stopping the mixer once or twice to scrape down the sides. Add the egg yolks one at a time, making sure each is incorporated before adding the next. Scrape the bowl as necessary to keep the mixture smooth. Add the vanilla and continue beating until the mixture is aerated and lightened in colour.

6 Add the cooled chocolate and beat to combine.

7 With the mixer on low speed alternately add the sifted dry ingredients in 4 additions and the buttermilk in 3 additions. Stop the mixer just before the last bit of flour is incorporated. Remove bowl from machine and mix by hand with a rubber spatula just until the batter is smooth.

8 In a separate bowl, beat egg whites with cream of tartar just until they are stiff but not dry. They should form soft peaks when the beaters are lifted. Fold one-quarter of the beaten whites into the batter, then gently but thoroughly fold in the remaining whites.

9 Divide the batter among the prepared cakepans, and using an offset metal spatula or the back of a spoon, spread the batter so the tops are level. Despite the different shapes and sizes of pans, the level of batter in each one should be the same.

10 Place in the oven, staggering the pans among the racks. Bake for 30 to 35 minutes, rotating the pans about halfway through, until the tops of the cakes are just firm to the touch.

11 Remove from oven and cool on wire racks. Once cool, remove from pans. (The layers can be individually wrapped and stored overnight, or frozen.)

12 Reduce oven to 250°F (120°C).

13 Line a baking sheet with parchment paper.

14 Crumble the 8-inch (20-cm) cake into small pieces onto the baking sheet. Place in oven and dry for 1½ hours or until cake is dry and crispy.

15 For the whipped ganache, place the chocolate in a medium bowl. In a small saucepan over medium-high heat, bring the cream to a boil and immediately pour over the chocolate. Gently whisk until the chocolate is completely melted and smooth. Cool to room temperature.

16 Whip the butter and chocolate mixture together in an electric mixer fitted with the whisk attachment. Continue whipping until the mixture is fluffy and light in colour.

17 To assemble, place 1 square cake layer on a cardboard round or flat plate. Spread some whipped ganache over the top. Top with some of the dried cake pieces, lightly pressing them into the ganache. Spread a little more ganache over top. Place the second square layer on the ganache layer. Repeat this process on a separate cardboard round or flat plate with the 2 round layers.

18 Using a serrated knife, cut the round cake in half and place 1 piece on 1 side of the square cake. Repeat with remaining half circle to form a heart shape.

19 Coat the top and sides of the cake with a thin layer of ganache to set the crumbs. Refrigerate the cake for 15 to 20 minutes or until the ganache is firm.

20 With a clean spatula, coat the cake with a final layer of ganache.

21 With a rolling pin, or in a food processor, crush the remaining dried cake into fine crumbs. Pat them around the sides of the cake and sprinkle on top to cover. Using a fine sieve, dust the top with cocoa powder, and the edges with icing sugar.

22 Refrigerate the cake just until firm enough to transfer to a clean cake plate. Serve at room temperature.