With rich pastry cream sandwiched between two luscious hot milk & butter cakes draped in chocolate ganache, Boston Cream Pie is worth the effort!
[Side Note: a version of this post first appeared on my OutlanderCast column, April 3, 2019]
It’s a special day (or maybe just a day you want to make special).
You’ve got some time on your hands, and a yen for something rich, elegant, and incredibly yummy.
I've got five words for you...Boston Cream Pie, from scratch!
And if you don't want to have a big cake on hand, you can make a mini Boston Cream Pie. Perfect for a small group!
Boston Cream Pie isn't pie
Before we go further, let’s get the name question out of the way. Boston Cream Pie is a descendant of earlier desserts called American pudding-cake pies.
According to “All Things Knowledge” (aka Wikipedia), this dessert “acquired its name when cakes and pies were cooked in the same pans, and the words were used interchangeably.”
The current name is because this combination of cake-pastry cream-ganache was created at the Parker House Hotel in Boston in the late 19th century.
What goes into Boston Cream Pie
There are three major components to a Boston Cream Pie recipe: the cake, the pastry cream, and the chocolate ganache.
I adapted my Mini Boston Cream Pie recipe from King Arthur Flour, although the current recipe on their website has been changed from the one I use. It's a scaled-down version of their older recipe baked in two 6-inch round cake pans (yay, math!).
For a full-sized cake, just double all the ingredients, and bake the cake in two 9-inch round cake pans.
Hot Milk & Butter Cake
The cake is a classic hot-milk-and-butter cake, so called because you use…uhm…hot milk and melted butter in the batter. This cake is a richly flavored sponge, moist and tall.
A Hot Milk and Butter cake recipe is made in four steps:
- Beat the egg and sugar until thickened, then add the vanilla extract.
- Sift the cake flour, baking powder, and salt together. Add to the egg mixture.
- Warm the milk and butter to a simmer, then remove from heat. Stir until the butter is melted. Slowly add to the cake batter (the batter will be thin).
- Divide into the cake pans and bake until the layers are a deep golden brown.
One trick to ensure the cake layers will be even is to use Bake-Even strips. They wrap around the cake pans and insulate the edges, allowing them to bake evenly with the center.
Check out this Port Wine Chocolate Cake recipe to see the Bake-Even strips in action. No leveling needed!
Allow the layers to cool completely before assembly. You don't want to melt the pastry cream.
Vanilla Bean Pastry Cream
Use a fresh vanilla bean in your pastry cream
This pastry cream is flavored with fresh vanilla bean seeds.
Did I say vanilla bean seeds? No, flecks of flavor, more like!
I don't always use a fresh vanilla bean in my baking, but I do when the vanilla will be showcased, like in pastry cream or Magic Custard Cake.
To use a fresh vanilla bean, split it lengthwise and scrape up the seeds with the back of a paring knife, then stir those flavor flecks into the milk mixture along with the spent bean (nothing goes to waste here!).
You can always substitute one teaspoon of pure vanilla extract for the vanilla bean, if you wish. Just add it in with the butter after you've cooked the custard.
How to temper eggs for custard
What does tempering eggs mean?
When you need to add the egg yolks to the hot milk, it's important to warm them first. This step helps avoid little pieces of cooked egg in your pastry cream. It's helpful to start with room-temperature egg yolks.
After you bring the milk just to a simmer (little bubbles around the edges), take about a half cup and slowly add it to the yolks while whisking constantly. Do it a second time, again whisking.
When the eggs feel warm to the touch, you can add the yolk mixture back in with the rest of the hot milk, still whisking. That's tempering the eggs.
To finishing cooking the pastry cream, bring the mixture to a boil and whisk until it's thickened and the whisk leaves a trail. Remove from the heat and quickly add in the butter.
You'll want to make the pastry cream while the cakes are in the oven to give it plenty of time to chill before assembly.
Pastry Cream tips
I like to strain the finished cream through a fine mesh strainer, just in case there's any cooked egg. It's also easier to remove those spent vanilla beans.
Don’t toss the vanilla bean after you've finished making the pastry cream. Instead rinse the bean, then place it in a jar and cover with vodka to make your own vanilla extract.
You'll be rewarded with vanilla extract that's both free and better than what you can buy.
By the way, if you'd like to make vanilla pudding, use this pastry cream recipe, just reduce the cornstarch to two tablespoons. Making chocolate pudding uses the same technique. Both are guaranteed to be much better pudding than anything you can get out of a box!
Dark Chocolate Ganache
Chocolate ganache is, well, fudgy chocolate nirvana, especially if you use dark chocolate. ‘Nuff said.
It can be used to glaze cakes (as it is here) or as the filling for tarts and truffles. The corn syrup helps to give the ganache stability and a beautiful sheen.
To make chocolate ganache, you start with equal parts chocolate and heavy cream, by weight. A kitchen scale is helpful here.
Making a recipe for chocolate ganache is incredibly easy.
Just warm the heavy cream, then pour it over chopped chocolate. Cover and let the mixture sit for a couple of minutes, then stir until smooth. Finally, add the corn syrup and vanilla extract.
There's nothing to it!
Assemble the Boston Cream Pie
You'll want to give yourself plenty of time (several hours or overnight) for the cake layers to cool and the pastry cream to be thoroughly chilled.
When you're ready to assemble, that's when you'll make the chocolate ganache recipe.
Once you've glazed the assembled Boston Cream Pie, let the ganache set for a few minutes before serving.
One elegant dessert
Boston Cream Pie is one of those desserts that take a little time and patience to make, but the result is so incredible that it’s well worth the effort.
The hot milk and butter cake is moist and light, offset by the rich pastry cream. The dark chocolate ganache adds a luxurious counterpoint that tempers the sweetness while adding body to the cake.
Yes, this is truly an elegant dessert.
Whether you make a small Boston Cream Pie or the full-sized version, you’ll be rewarded with a rich, elegant, and oh, so yummy dessert.
It’ll make any day special!
Slainté! L’chaim! Cheers!
Recipes using custard
Custards come in many forms, but the method is similar across the board. Luckily, the technique is easy to master, and you'll be able to make a whole range of treats!
Mini Boston Cream Pie
For the cake
- 1 cup granulated sugar
- 1 large egg, at room temperature
- 1 tsp pure vanilla extract
- 1 cup cake flour
- 1 tsp baking powder
- ½ tsp kosher salt
- ½ cup milk
- 3½ Tbsp unsalted butter, softened
For the pastry cream
- 1½ cups milk
- ½ vanilla bean, split (or 1 tsp vanilla extract)
- ⅓ cup granulated sugar + 1 Tbsp, divided
- 3 large egg yolks, at room temperature
- 3 Tbsp cornstarch
- 1½ Tbsp unsalted butter
For the ganache
- ½ cup dark chocolate, chopped, see Recipe Notes
- ⅓ cup heavy cream, see Recipe Notes
- 1 tsp light corn syrup
- ½ tsp pure vanilla extract
- Make the cake: Beat the sugar and egg together at medium-high speed using a stand mixer fitted with a paddle attachment (or hand mixer) until very thick, about 3 to 4 minutes (butter will fall from the paddle in thick ribbons). Beat in the vanilla extract.
- Using a sifter, combine the flour, salt, and baking powder in a small bowl. Add to the egg mixture and beat on low speed just until combined, about 1 minute.
- In a saucepan set over medium heat, bring the milk and butter just to a simmer. Remove the pan from the heat, and stir the mixture until the butter is completely melted.
- With the mixer going, slowly add the hot milk mixture to the cake batter, mixing until everything is well combined. Scrape the bowl and mix briefly, just until smooth. The batter will be very thin.
- Wrap the cake pans with Bake-Even strips, if desired (you won't be a need to level the cakes later). Divide the batter into the prepared pans, checking carefully for lumps of flour (smash or remove them as you spot them).
- Bake the cakes for 30 to 35 minutes, until they're a deep golden brown and beginning to pull away from the sides of the pan.
- Remove the cakes from the oven, run a table knife around the edges, and cool in the pan for 10 minutes. Turn them out onto a rack to cool completely.
- Make the pastry cream: Bring the milk, vanilla bean (if using), and half of the sugar just to a simmer in a large nonreactive saucepan.
- Whisk the egg yolks in a mixing bowl and gradually add the remaining sugar. Whisk in the cornstarch to combine.
- Take about a ½ cup of the scalded milk and slowly add it to the yolk mixture, whisking constantly. Return the yolk mixture to the pan and cook, whisking vigorously, until the cream boils and is well thickened. Allow the pastry cream to boil approximately 1 minute longer, stirring constantly. Don't overcook the pastry cream to avoid overcooking the eggs.
- Remove the pastry cream from heat. Fold in the vanilla extract (if using) and butter; stir until the butter melts. Do not overmix, as this will thin the custard.
- Strain the custard through a fine mesh strainer into a clean mixing bowl, removing the vanilla bean. Chill in an ice bath, then refrigerate until needed, covered with plastic wrap on the surface of the custard (this prevents a buildup of “skin” on the surface of the custard).
- Assemble the cake: Level the cakes (if needed). Place one of the cakes, right side up, on a cake plate. Top with a good amount of the pastry cream, spreading it right to the edges (you want at least ½-inch of filling inside when the cake is assembled). Place the top layer, upside down, on the filling.
- Prepare the ganache: Place the chopped chocolate in a bowl. Heat the cream to a simmer either on the stove in a small saucepan or in the microwave. Pour the cream over the chopped chocolate, cover, and let sit for 2 minutes, then stir together until smooth and lump free. Add the corn syrup and vanilla and stir well.
- Pour the ganache over the filled cake and let set for a few minutes. Serve and enjoy!