Boston Cream Pie is one of those desserts that’s kind of a hassle to make—but is totally worth the effort. You have to bake and cool the cakes. Make and cool the custard. Make and cool the chocolate frosting. Toast the almonds. Etc. But when our friend Foroct Fralion celebrated a rather auspicious birthday a few weeks ago, it only seemed proper to make him a Boston Cream Pie, one of his favorite treats. Here are step-by-step instructions for how to make one at home.
Boston Cream Pie usually shows up two ways: With or without toasted, sliced almonds on the sides. I make mine with the almonds, which is most traditional. You can leave them out and cover the sides completely with chocolate—or just let it drip down the sides. Completely up to you.
The History of the Boston Cream Pie
So Boston Cream Pie actually isn’t a pie at all—it’s a cake. Two layers of yellow cake (butter or sponge) filled with a thick custard, then topped with rich chocolate frosting.
It’s generally agreed that Boston Cream Pie was first made and served by French chef M. Sanzian right here at Boston’s Parker House Hotel. (Yep, the same place to produce those fabulous and fluffy Parker House rolls.)
Boston’s Omni Parker House Hotel
An important note on timing for Boston Cream Pie
Boston Cream Pie is best served the day that it’s assembled.
This Boston Cream Pie has four components: The cake, the custard filling, the chocolate frosting, and the toasted almonds. All of them need to be made, then cooled completely before assembling.
You can always make all the parts the night before, then assemble the cake the next day. If you do that, just bring the chocolate frosting up to room temperature before coating the cake to loosen it up a little.
Once the cake is assembled, plan enough time to chill it for an hour or two before serving.
Boston Cream Pie
1/2 cup butter (that’s 1 stick), softened on the counter for 20 minutes or so
1 cup sugar
3 egg yolks
1 tsp. vanilla extract
3/4 cup milk
2 cups cake flour
2 tsp. baking powder
pinch of salt
1/2 cup sugar
4 egg yolks
6 Tbls. flour
1 1/2 cups milk
2 tsp. vanilla extract
4 oz. semisweet chocolate, chopped
1/2 cup heavy cream
1 Tbls. butter
1 1/2 cups almonds, sliced
1 Tbls. butter
pinch of salt
Make the cake
Preheat your oven to 375 degrees. Spray 2 8-inch round cake pans with oil, then line with circles of parchment paper. Set them aside.
Combine the sugar and butter in the bowl of your mixer.
Beat them together until well combined.
Add in the egg yolks.
Beat again until well combined and kind of fluffy.
Scrape down the sides of your bowl with a spatula.
Add the milk.
Combine the flour, baking powder, and salt in a small bowl. Stir them together with a whisk to combine well. Toss the dry mixture into the butter/sugar in the mixing bowl.
Mix on medim-high for maybe 20 or 30 seconds to combine, just until the batter comes together.
The batter will be relatively thick and stiff, like this:
Give the batter a stir or two with a spatula to be sure that it’s mixed well and no dry ingredients remain in the very bottom of the bowl.
Divide the batter evenly between your two prepared cake pans.
Smooth it down with a spatula so it fills the whole pan and is relatively even.
Bake cake the 2 cakes for 20-23 minutes at 375 degrees.
They’re done when they’re golden brown on top and feel firm (not jiggly) in the middle when pressed with a finger. When inserted in the center, a toothpick should come out clean.
Cool the cakes in the pans for about 10 minutes. Then, gently run a knife around the whole edge to loosen it, and remove each cake from the pan. (Because you lined each pan with parchment paper, this should be easy.)
Set the cakes on a rack to cool completely.
If your cakes wound up a little crusty on the edges, like this, don’t worry. You’re going to trim those crisp edges right off when you assemble your Boston Cream Pie.
Make the custard
Fill a medium-sized pot with a few inches of water. Set it on the stove over high heat to bring it up to a boil.
Then put the sugar and egg yolks in a large heatproof bowl.
Whisk together until well combined.
Add the flour.
Whisk to combine.
Pour in the milk.
And the vanilla. (That’s my homemade vanilla extract!)
Whisk to combine. When your pot of water is boiling, drop the heat to low. Set the bowl on top of the pot of water.
Whisk it constantly for 5-7 minutes until it starts thicken.
Keep whisking until the custard gets very thick. It’s done when it coats the back of a spoon. Give it a taste. It should have a nice custard-y taste, without any hint of raw flour.
When it’s done, take it off the heat. Cool it on the counter to room temperature, then pop it in the fridge to chill it completely.
Make the chocolate frosting
Fill a medium-sized pot with a few inches of water. Set it on the stove over high heat to bring it up to a boil. (If you’re making the frosting right after the custard, just use the same pot of simmering water.)
Chop up the chocolate. Put it into a large heatproof bowl. Pour in the cream.
When your pot of water is boiling, drop the heat to low. Set the bowl on top of the pot of water.
Toss in the butter.
The chocolate should start to melt almost immediately. Whisk to combine.
Keep whisking until all the chocolate is melted and you have a uniform mixture.
Set the chocolate frosting aside to cool. As it cools, it will thicken up. If you put it in the fridge, keep a close eye on it. It can go from nice and thick to solid fudge in no time flat.
Toast the almonds
Melt the butter in a large, non-stick skillet over medium-high heat. Put the sliced almonds in the pan. Toss in a pinch of salt. Stir to coat the almonds with butter. Cook for a few minutes, stirring occasionally, until the nuts are fragrant and start to turn brown.
Set the toasted almonds aside to cool.
Assemble the Boston Cream Pie
Phew! OK, we’re finally at the point where we can put this whole thing together! Don’t do this until all of your components are completely cool. (If you try to put it together when any piece is warm, you’ll wind up with a slippery, drippy mess.)
Start by trimming your cakes. Carefully set them one on top of the other.
With a serrated bread knife, cut the edges off.
Go slowly, and press down on the top of the cake with one hand to keep it from ripping.
My trimmed cakes:
Should you have an accident with one of the cakes, like this, don’t fret. Just use that cake as the bottom layer. The custard filling will help glue the whole thing together once it gets cold in the fridge.
Set one cake on your serving platter, bottom side facing up. (Do this so that your custard goes on a flat—not slightly domed—surface.)
Grab the custard filling from the fridge. It should be nice and thick. Spoon it out onto the cake. Reserve a few spoonfuls of custard for later, to help stick the almonds to the side of the cake.
Spread the custard to the edges with a rubber spatula. Put the second cake right on top.
Grab your chocolate frosting. Spoon it out onto the top of the cake.
Spread it around until the top of the cake is covered.
Pop two toothpicks into the cake to hold the layers together for now, until it’s completely chilled.
With your finger, brush the leftover custard onto the edges of the cake, so it’s covered in a thin layer.
Press the toasted almonds onto the sides of the cake. They should stick nicely to the custard.
Keep going until all sides of the cake are covered in toasted almonds. Wipe any excess almonds and custard off your platter to clean it up. Then pop the cake into the fridge for a few hours to firm it up.
Serve and enjoy!