In 1855, a German-born pastry chef at Boston’s Parker House Hotel added a rich chocolate glaze to a custard-filled sponge cake known as Boston Pie, and a new American classic was born. This version (with a few changes here and there) comes from my book The Cake Book (HMH, 2006), and it hits all the right notes: light vanilla sponge cake + silky pastry cream filling + glossy dark chocolate glaze. One mouthful and you’ll recognize that although Bostonians might not know their pie from their cake, they sure do know a good thing when they taste it.
Makes one 9-inch cake, serving 10
Vanilla Pastry Cream Filling:
- 2 large (100 grams) eggs
- 2 large (37 grams) egg yolks
- ¼ cup (30 grams) cornstarch
- 1/8 teaspoon fine sea salt
- 2 cups (483 grams) whole milk
- ½ cup (100 grams) granulated sugar
- 3 tablespoons (42 grams) unsalted butter, softened
- 1 teaspoon vanilla paste or extract
- 1/4 cup (58 grams) heavy cream
Hot Milk Sponge Cake:
- 1 1/3 cups (133 grams) cake flour
- 1 1/4 teaspoons baking powder
- 1/4 teaspoon salt
- 1/2 cup (121 grams) whole milk
- 4 tablespoons (57 grams) unsalted butter, cut into tablespoons
- 3 large eggs, at room temperature
- 3/4 cup (150 grams) granulated sugar
- 1 teaspoon vanilla extract
Dark Chocolate Glaze:
- 3 ounces (85 grams) high-quality bittersweet chocolate 70%, finely chopped
- 7 tablespoons (101 grams) heavy cream
- 1/2 teaspoon vanilla paste or extract
Make the pastry cream:
- In a medium bowl, whisk together the eggs, egg yolks, cornstarch and salt until smooth.
- In a medium saucepan, combine the milk and sugar over medium heat and cook, stirring frequently, until the milk is heated through and begins to bubble around the edges. Remove the milk from the heat and slowly drizzle it into the egg mixture, whisking constantly. Scrape the egg mixture back into the saucepan and place over medium heat, whisking constantly until the mixture thickens and comes to a boil. Boil, whisking vigorously, for 10 more seconds, until the pastry cream is thick and glossy, then immediately remove from heat.
- Pour the pastry cream through a fine-mesh sieve set over a small bowl. Whisk in the butter, one tablespoon at a time, whisking until completely melted and incorporated. Whisk in the vanilla. Cover the cream with plastic wrap, pressing the plastic wrap against its surface to prevent a skin from forming. Refrigerate until chilled, at least 4 hours and up to 3 days. (You will add the cream later.)
Make the sponge cake:
- Position a rack in the center of the oven and preheat the oven to 350˚F. Grease the bottom and sides of a 9-inch cake pan, then line the bottom with a round of parchment paper. Dust the pan with flour and set aside.
- Sift together the cake flour, baking powder, and salt two times. Set aside.
- In a small saucepan, place the milk and butter over medium heat just until the butter is melted. Remove the pan from the heat and set aside.
- In the bowl of an electric mixer, using the whisk attachment, beat the eggs at high speed until blended, about 1 minute. Gradually add the sugar and vanilla extract and beat until pale and tripled in volume, about 6 minutes.
- Sift one-third of the flour mixture over the egg mixture and gently fold it in with a rubber spatula. Repeat with the remaining flour mixture in two more additions. Reheat the milk mixture to scalding. Add it all at once to the egg mixture and gently fold it in. Scrape the batter into the prepared pan. Bake the cake for 20 to 25 minutes, until the cake is golden brown and springs back when lightly touched and a cake tester inserted into the center comes out clean. Cool the cake in the pan, set on a wire rack, for 10 minutes.
- Run a paring knife around the edge of the pan and invert the cake onto the wire rack. Reinvert the cake (so that it is right side up) and cool completely.
Make the glaze:
- Place the chocolate in a bowl and set aside.
- Place the cream in a small saucepan and bring to a boil. Remove from heat and pour over the chocolate. Allow to stand for 1 minute, to allow the chocolate to melt. Whisk until smooth and emulsified. Stir in the vanilla extract. Cover the surface of the glaze with a piece of plastic wrap and let it cool for about 10 minutes before using.
Finish the pastry cream and assemble the cake:
- Using a long, serrated knife, cut the cake horizontally in half to make 2 layers.
- Remove the pastry cream from the refrigerator and transfer it to the bowl of an electric mixer. Add the 1/4 cup of heavy cream and, using the whisk attachment, beat the mixture at high speed until it is light and forms soft peaks, about 1 minute.
- Place one of the cake layers (save the smooth layer that was against the bottom of the pan for the top of the cake), cut side up, on a serving plate. Scrape the custard filling onto the layer and, using a small offset metal spatula, spread it into an even layer. Top with the other cake layer.
Glaze the cake:
- Pour the warm glaze over the top of the cake, allowing some of it to drizzle down the sides. Serve the cake immediately, or refrigerate and bring to room temperature before serving.