Boston Cream Pie

A Layered American Classic of Sponge Cake, Pastry Cream, and Chocolate Ganache

Though it’s called a “pie,” the Boston Cream Pie is truly a cake — and an extraordinary one at that. It brings together three essential dessert elements: a light vanilla sponge cake, rich vanilla pastry cream, and a glossy chocolate ganache topping. The result is a dessert that feels both old-fashioned and timeless.

Invented in the mid-1800s at the Parker House Hotel in Boston, this beloved dessert has stood the test of time. It’s the official state dessert of Massachusetts, and for good reason. Let’s explore what makes Boston Cream Pie a masterpiece — and how to make one in your very own kitchen.

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Table of Contents

1. What Is Boston Cream Pie?

2. Ingredients Overview

3. Tools You'll Need

4. Make the Pastry Cream

5. Bake the Sponge Cake

6. Prepare the Chocolate Ganache

7. Assemble the Cake

8. Chill and Serve

9. Tips for Success

10. Storage and Make-Ahead Instructions

11. Fun Variations

12. Final Thoughts

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1. What Is Boston Cream Pie?

Boston Cream Pie is a dessert consisting of:

• Two layers of sponge cake

• A thick layer of vanilla pastry cream in the middle

• A smooth chocolate ganache poured over the top

Traditionally, the sides of the cake are left bare (not frosted), letting the custard filling and glossy chocolate topping steal the show. It’s a simple concept, but when done right, it’s unforgettable.

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2. Ingredients Overview

Let’s break down each component of the Boston Cream Pie.

For the Pastry Cream (Custard Filling):

• 2 cups whole milk

• ½ cup granulated sugar

• ¼ cup cornstarch

• 4 large egg yolks

• 2 tablespoons unsalted butter

• 1½ teaspoons pure vanilla extract

• Pinch of salt

For the Sponge Cake:

• 1½ cups cake flour (or sifted all-purpose flour)

• 1½ teaspoons baking powder

• ¼ teaspoon salt

• 4 large eggs, at room temperature

• 1 cup granulated sugar

• ½ cup whole milk

• ¼ cup unsalted butter

• 1½ teaspoons vanilla extract

For the Chocolate Ganache:

• ½ cup heavy cream

• 4 oz semi-sweet or bittersweet chocolate, chopped

• 1 tablespoon corn syrup (optional, for shine)

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3. Tools You'll Need

• Two 9-inch round cake pans

• Mixing bowls

• Saucepan

• Whisk

• Electric mixer (hand or stand)

• Offset spatula

• Wire rack

• Cake stand or serving plate

• Fine mesh strainer (optional)

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4. Make the Pastry Cream

This luscious custard is the heart of a Boston Cream Pie.

Instructions:

1. In a medium saucepan, heat 2 cups milk over medium heat until steaming, but not boiling.

2. In a mixing bowl, whisk together ½ cup sugar, ¼ cup cornstarch, 4 egg yolks, and a pinch of salt until pale and smooth.

3. Slowly pour the hot milk into the egg mixture, whisking constantly to temper the eggs.

4. Return everything to the saucepan and cook over medium heat, whisking constantly until thick and bubbling — about 3–5 minutes.

5. Remove from heat and stir in 2 tablespoons butter and 1½ teaspoons vanilla.

6. Pour into a clean bowl, cover with plastic wrap pressed directly onto the surface (to prevent a skin), and chill in the refrigerator for at least 2 hours.

Pro Tip: Make the pastry cream a day in advance to save time and improve consistency.

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5. Bake the Sponge Cake

This light, airy cake provides the perfect contrast to the creamy filling.

Instructions:

1. Preheat your oven to 350°F (175°C). Grease and line two 9-inch round cake pans with parchment paper.

2. In a medium bowl, whisk together 1½ cups cake flour, 1½ teaspoons baking powder, and ¼ teaspoon salt.

3. In a large mixing bowl, beat 4 eggs with an electric mixer for 1 minute.

4. Gradually add 1 cup sugar, beating on high speed until the mixture is pale, thick, and has tripled in volume (about 5–7 minutes).

5. In a small saucepan, heat ½ cup milk with ¼ cup butter until butter is melted and the mixture is hot (but not boiling). Stir in vanilla.

6. Gently fold the dry ingredients into the egg mixture in three additions.

7. Slowly pour in the hot milk mixture, folding carefully until incorporated. Do not overmix.

8. Divide batter between the two pans and smooth the tops.

9. Bake for 22–25 minutes, or until the cakes are golden and spring back when touched.

10. Let cakes cool in the pan for 10 minutes, then turn out onto a wire rack to cool completely.

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6. Prepare the Chocolate Ganache

This rich glaze finishes the cake with elegance and flavor.

Instructions:

1. In a small saucepan, bring ½ cup heavy cream to a simmer over medium heat.

2. Remove from heat and add 4 oz chopped chocolate (and 1 tbsp corn syrup, if using).

3. Let sit for 1–2 minutes, then whisk until smooth and glossy.

4. Allow the ganache to cool for 10–15 minutes until it thickens slightly but is still pourable.

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7. Assemble the Cake

Now comes the fun part.

Steps:

1. Place one cooled cake layer on your serving plate.

2. Give your pastry cream a stir to loosen it, then spread it evenly over the bottom layer. Leave a small border (¼ inch) to prevent overflow.

3. Top with the second cake layer, aligning it carefully.

4. Pour the chocolate ganache over the top, using an offset spatula to gently spread it to the edges. Let it drip slightly down the sides.

Optional: For a neater look, chill the assembled cake for 15–20 minutes before pouring the ganache. This helps it stay in place.

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8. Chill and Serve

• Chill the finished cake in the refrigerator for at least 1 hour before serving. This allows the cream and ganache to set.

• Before serving, garnish with chocolate curls, dust with powdered sugar, or leave it classic and simple.

To slice cleanly, dip a sharp knife into hot water and wipe dry between each cut.

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9. Tips for Success

• Use cake flour if you want a truly soft and tender crumb.

• Room temperature eggs whip up more easily and give you maximum volume.

• Don’t skip the chill: Letting the pastry cream and ganache set helps with stability and texture.

• Make ahead: Each component can be made 1–2 days in advance.

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10. Storage and Make-Ahead Instructions

Refrigeration:

• Store the fully assembled cake in the refrigerator, covered, for up to 3 days.

Freezing:

• You can freeze the unfilled cake layers for up to 1 month. Thaw completely before assembling.

Make-Ahead Schedule:

• Day 1: Make pastry cream, bake cake layers. Chill separately.

• Day 2: Assemble and glaze the cake. Chill again before serving.

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11. Fun Variations

Feeling creative? Try these spins on the original:

Boston Cream Cupcakes:

• Bake cupcakes, core them, and fill with pastry cream.

• Top with ganache instead of frosting.

Boston Cream Pie Trifle:

• Layer cubes of sponge cake, pastry cream, and ganache in a glass bowl.

• Repeat for 2–3 layers and chill before serving.

Strawberry Boston Cream:

• Add a thin layer of sliced strawberries over the pastry cream.

• Pairs beautifully with the chocolate and custard.

Boston Cream Donuts:

• Fill yeasted donuts with pastry cream and dip the tops in ganache.

• A bakery favorite you can make at home!

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12. Final Thoughts

Boston Cream Pie is one of those desserts that rewards patience and attention. From the delicate sponge to the silky custard and decadent ganache, each layer plays a vital role in the experience. It’s nostalgic, elegant, and crowd-pleasing all at once.

While it may take a few steps, none are difficult. And the result? A showstopping cake that feels like a love letter to classic baking.

Whether you’re honoring tradition or starting a new one, this recipe is a must-bake. Once you serve it, don’t be surprised if everyone asks, “When are you making that again?”