Classic Boston Cream Pie Recipe (From Scratch)

There is a reason the Boston Cream Pie has remained a beloved classic for over a century: it is the perfect trifecta of airy sponge cake, rich vanilla custard, and decadent chocolate ganache. This from-scratch recipe yields a show-stopping dessert that tastes even better than it looks, featuring a fail-proof filling that holds its shape perfectly for that iconic, beautiful slice.

🍫 The Ingredients

This timeless dessert transforms simple, high-quality pantry staples and fresh dairy into a sophisticated three-layered masterpiece that tastes far more complex than its humble components suggest. Find ingredient notes (including substitutions and variations) below.

📝 Ingredient Notes & Substitutions

• Whole Milk: This is essential for a rich, sturdy pastry cream; while 2% milk can work in a pinch, avoid skim milk as the custard will lack the necessary body and flavor.
• Cornstarch: This serves as the thickening agent for the filling; if you need a substitute, you can use arrowroot powder or double the amount of all-purpose flour (though flour will result in a slightly cloudier appearance).
• All-Purpose Flour: This provides the perfect structure for the hot milk sponge, but for an even finer, more delicate crumb, you can swap it for an equal amount of cake flour.
• Semi-Sweet Chocolate (56%): For the smoothest ganache, use a high-quality baking bar rather than chocolate chips; if you prefer a deeper, less sweet flavor, bittersweet chocolate (60% or higher) is an excellent alternative.
• Light Corn Syrup: This is the secret to achieving a professional, high-gloss finish on your ganache; if you prefer not to use it, you can substitute it with honey or simply omit it, though the glaze will be more matte.
• Unsalted Butter: Using unsalted butter allows you to control the salt content precisely; if you only have salted butter on hand, simply omit the additional pinch of salt from the recipe.

Refer to the recipe card (with video) below for a full list of ingredients and measurements.

📌 Tips and Tricks for the Perfect Boston Cream Pie

• Temperature Matters for Volume: Ensure your eggs are truly at room temperature before beating them with the sugar; this allows the eggs to trap more air, resulting in a taller, fluffier sponge cake.
• The “Skin” Secret: To prevent a rubbery skin from forming on your pastry cream, press plastic wrap directly onto the surface of the custard while it is still warm and keep it there until you are ready to assemble the cake.
• Strain for Smoothness: For a professional, melt-in-your-mouth texture, always pass your cooked pastry cream through a fine-mesh sieve; this catches any tiny bits of cooked egg and ensures a perfectly silky filling.
• Master the “Slow Drip”: Timing is everything with ganache. Let it sit for about 10–15 minutes until it is slightly thickened but still pourable; if it’s too hot, it will run right off the cake, but if it’s the right temperature, it will create those beautiful, thick drips.
• The Clean Slice Technique: To get those stunning, Pinterest-worthy slices Wesley is looking for, dip a sharp knife in hot water and wipe it completely dry between every single cut to prevent the chocolate and cream from smearing.
• Don’t Rush the Chill: While it’s tempting to serve it immediately, letting the assembled cake rest in the fridge for at least 30 minutes “sets” the layers, ensuring the pastry cream stays put instead of squishing out the sides when you cut it.

👩🏼‍🍳 How to Make the Perfect Vanilla Pastry Custard

1. Step 1: Whisk the milk and sugar in a saucepan and bring to a slight simmer over medium heat.

2. Step 2: Use a stand mixer or hand mixer to whisk the egg yolks with the sugar, cornstarch, and salt until pale, about 3 minutes.

3. Step 3: Pour about half of the warm milk/sugar liquid into the egg/sugar mixture, whisking constantly. This is tempering the eggs.

4. Step 4: Pour the tempered eggs from the bowl into the saucepan with the simmering milk. Whisk constantly to prevent the eggs from scrambling.

5. Step 5: Whisk and stir until thickened to the consistency of custard. Remove from the heat and stir in the softened butter and vanilla.

6. Step 6: Strain the custard through a fine-mesh sieve into a bowl. Press plastic wrap onto the surface of the custard and chill while you make the sponge cake.

👨‍🍳 How to Make a Hot Milk Sponge Cake

1. Step 1: In a medium bowl, whisk together the flour, baking powder, and salt.

2. Step 2: Heat the whole milk and cubed butter in a small saucepan over medium heat until melted and barely simmering.

3. Step 3: Meanwhile, beat the eggs with the sugar on high until they become pale and slightly thickened, about 4 to 5 minutes.

4. Step 4: Turn the mixer to low, and alternatively add the flour mixture and the hot milk mixture, starting and ending with the flour mixture.

5. Step 5: Grease and flour two 9-inch cake pans and then split the batter between them both.

6. Step 6: Bake for 15 to 18 minutes, until an inserted toothpick comes out clean. Remove from the oven, let rest for 10 minutes, invert the cakes onto a baking rack, remove the parchment paper, and let rest until completely cooled.

🧑🏾‍🍳 How to Assemble a Classic Boston Cream Pie

1. Step 1: Heat the cream and then pour it over the chopped chocolate with the light corn syrup. Let rest.

2. Step 2: Place one of the sponge cakes on a circular cake stand and top with cooled pastry cream. Spread to about ½-inch from the edge of the cake.

3. Step 3: Stir the chocolate with the warm cream until smooth and fully incorporated.

4. Step 4: Top with the other sponge cake and smooth the pastry cream along the edges of the cake.

5. Step 5: Pour the ganache over the top of the cake and spread to the edges, allowing some to slightly spill over the sides.

6. Step 6: Chill for 30 minutes, or until the ganache sets. Slice and serve!

🙋🏽‍♂️ Frequently Asked Questions

🍰 Other Classic Cake Recipes

Ready to make the best cake this side of…well…Boston? Go for it!

And when you do, be sure to take a photo of it, post it on Instagram, and tag @HowToFeedaLoon and hashtag #HowToFeedaLoon!