A pie that’s actually a cake, invented by a French chef but named for an American city, Boston Cream Pie sounds like a riddle but tastes like a dream – soft yellow cake filled with vanilla pastry cream and topped with shiny dark chocolate ganache.
Your eyes are not playing tricks on you – these are Mini Boston Cream Pies. You can make a standard, 9-inch cake with this recipe, but just for fun this time I decided to make these cute, single-serving minis.
I used these hamburger bun pans from King Arthur Flour and ended up with eight 4-inch minis. If you don’t have something like this you could use individual 4-inch cake pans, or 10-ounce Pyrex custard cups, or even jumbo muffin tins.
Depending on the size and shape of the pans you use, the surface area for spreading the pastry cream and ganache will vary. This recipe provides for a generous amount of both, to cover all possibilities.
When I make the 9-inch version of this cake, I actually don’t use all the pastry cream – I like to add just enough so it soaks into the soft cake layers and holds them together, just peeking out along the edges but not overflowing. Pastry cream is not as thick as frosting, and doesn’t work like frosting to glue the cake layers together – add too much and the top layer of your cake may start to slide around. This is the reason we slice one layer in half rather than baking two thinner layers – exposing the pastry cream to the rough, porous cut edge of the cake gives it something to cling to, as opposed to the smooth surface of an uncut cake layer. It’s also the reason I recommend chilling the filled cake for an hour before adding the ganache; it gives the pastry cream time to firm up inside the cake.
Speaking of the ganache, I use it all – can’t have too much chocolate. I make mine extra thick so it piles up on top of the cake, and tips over the edges in glossy, lavalike flows.
Making Boston Cream Pie ahead and what to do with leftovers:
- The pastry cream needs to chill for several hours or overnight, so I make it a day ahead.
- You can make the entire Boston Cream Pie one day ahead. Don’t cover the ganache with anything that will touch it, like plastic wrap – store a full sized cake under a cake dome, and minis in a single layer in large, flat airtight containers.
- Leftovers will keep for several days, stored in the fridge as described above. If you’ve made the full-sized version, press a piece of plastic wrap against the cut surface to keep it from drying out.
- You may not use all the pastry cream in the assembly of this cake. Whatever pastry cream you have left over will keep for several days and can be made into any number of impromptu desserts. Top it with fresh berries and whipped cream, layer it into a trifle, scoop it into puffed pastry cups or cannoli shells.
To see these Mini Boston Cream Pies as part of a complete menu, including a game plan for timing for all the dishes, see my post for Saturday February 13, 2021.
Boston Cream Pie
This recipe makes one 9-inch cake, or approximately eight single-serving-sized cakes, depending on the size and shape of pans you use. Whatever size pans you're using, fill them no more than 2/3 full with batter to avoid overflowing, and adjust the baking time as needed. Four-inch cakes will bake in 18 to 22 minutes, while cakes baked in deeper cups such as muffin cups may take a few minutes more.
Ingredients
- For the pastry cream:
- 1 1/3 cups whole milk
- 4 large egg yolks
- 1/3 cup granulated sugar
- 4 tablespoons cornstarch
- Large pinch of kosher salt
- 2 tablespoons unsalted butter at room temperature, preferably European style
- 1 teaspoon pure vanilla extract
- For the cake:
- ¾ cup whole milk
- 8 tablespoons unsalted butter at room temperature, preferably European style, plus additional for the pan
- 1¾ cup (7 3/8 ounces or 210 grams) all-purpose flour
- 1¾ teaspoon baking powder
- ¾ teaspoon Diamond Crystal kosher salt, or 3/8 teaspoon Morton’s
- 3 large eggs
- 1 cup granulated sugar
- 1 teaspoon pure vanilla extract
- For the ganache:
- ¾ cup heavy cream
- 1½ cups (9 ounces) semisweet chocolate chips
- 1 tablespoon light corn syrup or Lyle’s Golden Syrup
Directions
- Step 1 Make the pastry cream. Heat the milk in a medium saucepan over medium heat until it just comes to a simmer. Meanwhile, combine the eggs and sugar in a medium bowl and whisk until well blended. Whisk in the cornstarch and a pinch of salt. Place the bowl on a kitchen towel to stabilize it.
- Step 2 When the milk is simmering, use a ladle or measuring cup to pick up about ½ cup of the hot milk. Slowly add the milk to the egg mixture while whisking vigorously with your other hand. Then add the egg mixture to the milk in the saucepan, pouring slowly with one hand and whisking with the other. Continue whisking until the mixture thickens and just comes to a low boil. Cook for another minute, whisking vigorously. Remove the pot from the heat and add the butter and whisk until it’s melted and incorporated. Whisk in the vanilla.
- Step 3 Pass the pastry cream through a fine mesh sieve into a medium bowl, pressing with a silicone spatula to push the mixture through the sieve. Let the pastry cream cool until it’s just warm to the touch, stirring frequently. When the cream is no longer hot, press a piece of plastic wrap directly on the surface of the custard to keep a skin from forming. Chill the pastry cream until very cold, at least 3 hours, preferably overnight.
- Step 4 Make the cake. Heat the oven to 325 degrees with a rack in the center position. Generously butter a 9-inch round cake pan with 2-inch sides. Line the bottom of the pan with a circle of parchment paper, and butter the parchment.
- Step 5 Heat the milk and butter together in a saucepan over medium heat until the mixture comes to a simmer. Remove the pan from the heat and let the mixture cool to lukewarm.
- Step 6 Mix the flour, baking powder and salt together with a whisk until well blended.
- Step 7 Combine the eggs and sugar in the bowl of a stand mixer and beat on medium-high speed until very pale and thick, 5 minutes. Don’t rush this step, it’s important to incorporate air into the batter to help the cake rise.
- Step 8 Beat in the vanilla, then add the flour and stir with the mixer on low speed just until the batter is combined.
- Step 9 Spread the batter in the prepared pan and smooth the top. Bake until a tester comes out clean, 30 to 35 minutes.
- Step 10 Transfer the pan to a cooling rack and cool the cake in the pan for 10 minutes. Run a knife around the inside edge of the pan to loosen the cake, then carefully turn the cake out, right side up on the rack, to cool completely.
- Step 11 To begin the assembly, once the cake is completely cool, use a large serrated knife, with the blade held parallel to the work surface, to carefully cut the cake into two layers. Place the bottom layer, cut side up, on a cake plate. Spread the pastry cream on the cake, spreading it out in a thin layer and gently pushing it out just to the edge of the cake. Keep the layer of cream rather thin at the edge, and pile it a little thicker in the center. Very gently set the top layer of the cake onto the cream with the cut side down. Don’t press down, or you’ll push the filling out. Chill the cake uncovered for 1 hour.
- Step 12 Make the ganache. Bring the cream to a simmer in a small saucepan over medium heat. Put the chocolate chips in a medium heat safe bowl. Pour the hot cream over the chocolate and let it sit, without stirring, for 2 minutes. Add the Lyle’s (or corn) syrup and stir the mixture until the chocolate is melted and the mixture is completely smooth. Let the ganache sit for 3 minutes to thicken just slightly. It will thicken a bit when it hits the cold cake, so it’s ready to use when it’s pourable but not runny. Dollop the ganache over the center of the cake, gently pushing it out toward the edge and letting some of the ganache flow thickly down the sides.
- Step 13 Serve immediately, or chill uncovered for up to several hours.
