Boston Cream Pie

Name: Boston Cream Pie
Prep time: 40 min
Cook time: 35 min
Total time: 1 h 15 min
Yield: 8 servings
Cuisine: American
Ingredients: 1½ cups (180 g) all-purpose flour, sifted twice; 1½ teaspoons (7 g) baking powder; ¼ teaspoon (1½ g) fine sea salt; 4 whole large eggs, at room temperature, separated into yolks and whites; 1 cup (200 g) granulated sugar; 1 teaspoon (5 ml) vanilla extract; 1¾ cups (420 ml) whole milk; 1 whole large egg, at room temperature; 3 whole large egg yolks; ½ cup (100 g) granulated sugar; 3 tablespoons (28 g) cornstarch; ⅛ teaspoon (¾ g) fine sea salt; 1½ teaspoons (7½ ml) vanilla extract; 1 tablespoon (14 g) unsalted butter, cold, cut into small pieces; 4 ounces (113 g) dark chocolate (70% cacao), chopped; 1 tablespoon (14 g) unsalted butter; ⅓ cup (80 ml) heavy cream; ½ teaspoon (2½ ml) vanilla extract

From the MyKitchenBank Kitchen

A showstopping American classic with two layers of tender, airy sponge cake sandwiching a smooth vanilla custard filling, all topped with a sleek chocolate glaze. The cake is light and fluffy, the custard is rich and creamy, and the dark chocolate topping provides the perfect finish. This elegant dessert is surprisingly approachable for home bakers.

Prep: 40 min
Cook: 35 min
Wait: 1 hr 30 min
Total: 2 hr 45 min
Makes: 1 cake (8 slices)

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Ingredients

8 servings

For the Cake
1½ cups (180 g) all-purpose flour, sifted twice
1½ teaspoons (7 g) baking powder
¼ teaspoon (1.5 g) fine sea salt
4 whole large eggs, at room temperature, separated into yolks and whites
1 cup (200 g) granulated sugar
1 teaspoon (5 ml) vanilla extract
For the Custard
1¾ cups (420 ml) whole milk
1 whole large egg, at room temperature
3 whole large egg yolks
½ cup (100 g) granulated sugar
3 tablespoons (28 g) cornstarch
⅛ teaspoon (0.8 g) fine sea salt
1½ teaspoons (7.5 ml) vanilla extract
1 tablespoon (14 g) unsalted butter, cold, cut into small pieces
For the Chocolate Glaze
4 ounces (113 g) dark chocolate (70% cacao), chopped
1 tablespoon (14 g) unsalted butter
⅓ cup (80 ml) heavy cream
½ teaspoon (2.5 ml) vanilla extract

Equipment (8)

Two 8-inch (20 cm) round cake pans
Parchment paper
Electric mixer
Medium and small saucepans
Whisk
Mesh sieve or fine strainer
Offset spatula
Cooling racks

Steps

Before you start

Bring 4 eggs (for cake) and 1 egg (for custard) to room temperature
Preheat oven to 375°F (190°C)
Sift flour twice before measuring
Read through the entire recipe—the custard must cool fully before assembly

1
Prepare pans
- Line the bottoms of two 8-inch (20 cm) round cake pans with parchment paper.
- Lightly butter the sides.
- Set aside.
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Tip: Parchment paper prevents sticking and makes cake removal easier.
2
Combine dry ingredients
- In a medium bowl, whisk together the sifted flour (1.5 cups / 180 g), baking powder (1.5 teaspoons / 7 g), and salt (0.25 teaspoon / 1.5 g).
- Set aside.
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Tip: Sifting twice aerates the flour and prevents lumps in the final cake.
3
Whip egg whites
- In a large bowl with an electric mixer on medium-high speed, beat the 4 egg whites until stiff peaks form, about 4–5 minutes.
- Transfer to another bowl and set aside.
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Ready when: Whites form stiff, glossy peaks that stand upright when the beater is lifted.
Tip: Ensure the bowl and beaters are completely grease-free, or the whites won't whip properly.
4
Beat yolks and sugar
- In the same (now-empty) mixer bowl, beat the 4 egg yolks with the sugar (1 cup / 200 g) on medium-high speed for 3–4 minutes until the mixture is pale, thick, and falls in ribbons from the beater.
- Add the vanilla extract (1 teaspoon / 5 ml) and beat for 30 seconds more.
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Ready when: The mixture is pale yellow, very thick, and holds a ribbon shape when the beater is lifted.
Tip: This step incorporates air, which is crucial for the cake's light, fluffy crumb.
5
Fold in dry ingredients
- Gently fold the dry ingredients into the yolk mixture using a rubber spatula, folding about 12–15 times until just combined.
- Avoid overmixing.
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Ready when: The mixture is uniform but still slightly thick.
Tip: Gentle folding preserves the airiness you've built into the yolks and prevents a dense crumb.
6
Fold in whites
- In two batches, gently fold the whipped egg whites into the batter using a rubber spatula.
- After the first batch is partially incorporated, add the second batch and continue folding until just combined and no white streaks remain.
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Ready when: The batter is uniform, light, and fluffy with no visible white streaks.
Tip: Fold gently to keep the batter light—overmixing will deflate the whites and toughen the cake.
7
Bake cakeOven 375°F / 190°C
- Divide the batter evenly between the prepared pans.
- Smooth the tops with an offset spatula.
- Place both pans in the preheated 375°F (190°C) oven on the middle rack and bake for 22–25 minutes until a toothpick inserted in the center comes out clean and the tops are golden and spring back when gently pressed.
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Ready when: Toothpick test shows no wet batter, cake springs back when lightly pressed, and tops are light golden.
Tip: Do not open the oven door before 20 minutes, as drafts can collapse the delicate cake.
8
Cool cakes
- Remove both pans from the oven and let cool in the pans for 10 minutes.
- Turn the cakes out onto cooling racks and cool completely, about 30 minutes.
- Remove parchment paper once they're cool enough to handle.
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Ready when: Cakes are no longer warm to the touch and have cooled to room temperature.
Tip: Cooling on a rack (not in the pan) prevents condensation from making the bottoms soggy.
9
Make custard baseOven 170°F / 75°C
- In a medium saucepan, heat the milk (1.75 cups / 420 ml) over medium heat, stirring occasionally, until small bubbles form around the edges (about 170°F / 77°C).
- Do not boil.
- Meanwhile, in a bowl, whisk together 1 whole egg, the 3 egg yolks, sugar (0.5 cup / 100 g), cornstarch (3 tablespoons / 28 g), and salt (0.125 teaspoon / 0.75 g) until pale and smooth.
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Ready when: Milk steams and small bubbles form around the edge; egg mixture is pale and smooth.
Tip: Tempering the egg mixture prevents scrambling. The cornstarch helps set the custard to the right consistency.
10
Temper and cook custardOven 160°F / 70°C
- Slowly pour the hot milk into the egg mixture while whisking constantly.
- Pour the mixture back into the saucepan and cook over medium heat, whisking constantly, for 3–4 minutes until the custard is thick enough to coat the back of a spoon and reaches 160°F (71°C) on a thermometer for food safety.
- Remove from heat.
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Ready when: Custard coats the back of a spoon and reaches 160°F (71°C); mixture is thick and smooth.
Tip: Constant whisking prevents lumps and ensures even cooking. The 160°F temperature is food-safe.
11
Finish custard
- Pass the custard through a fine mesh sieve into a clean bowl to remove any lumps.
- Stir in the vanilla extract (1.5 teaspoons / 7.5 ml) and the cold butter pieces (1 tablespoon / 14 g), stirring until the butter melts and the custard is smooth.
- Press plastic wrap directly onto the surface of the custard and refrigerate for at least 45 minutes until chilled and set.
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Ready when: Custard is thick, cool, and no longer hot to the touch.
Tip: Straining ensures a silky-smooth filling. The butter enriches the flavor and helps set the texture.
12
Make chocolate glaze
- Place the chopped chocolate (4 ounces / 113 g) and butter (1 tablespoon / 14 g) in a small heatproof bowl.
- In a small saucepan, heat the cream (0.33 cup / 80 ml) over medium heat until steaming (do not boil).
- Pour the hot cream over the chocolate and butter, cover with plastic wrap for 30 seconds, then whisk until smooth and glossy.
- Stir in the vanilla extract (0.5 teaspoon / 2.5 ml).
- Let cool for 5 minutes until it reaches a pourable, coating consistency.
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Ready when: Glaze is smooth, glossy, and pourable, thick enough to coat the back of a spoon.
Tip: Covering the chocolate with steam helps it melt evenly without seizing. Use the glaze while still warm for an even finish.
13
Assemble pie
- Place one cooled cake layer on a serving plate.
- Spread the chilled custard filling (about 1 cup / 240 ml) evenly over the cake layer, leaving a 0.5-inch (1.25 cm) border.
- Place the second cake layer on top, pressing very gently to secure.
- Immediately pour the warm chocolate glaze over the top and use an offset spatula to spread it in an even layer, allowing some to drip naturally down the sides.
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Ready when: Chocolate glaze is spread evenly over the top and partially down the sides.
Tip: Work quickly while the glaze is warm for a smooth, glossy finish. Chilled cake layers help support the filling.
14
Chill and serve
- Refrigerate the assembled pie for at least 15 minutes to allow the chocolate glaze to set before serving.
- Slice with a sharp, warm knife (dip it in hot water and wipe between cuts) to make clean, elegant slices.
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Ready when: Chocolate glaze is no longer sticky and holds its shape.
Tip: A warm knife cuts through the chocolate without cracking or dragging the filling.

Good to know

Tips

Separating eggs takes patience: crack each egg carefully over a small bowl, then transfer the yolk to your mixing bowl using the empty shell halves. This prevents any yolk from slipping into the whites and ruining the whole batch.
If your custard looks grainy or lumpy after cooking, strain it through a fine sieve—this is a common issue and easily fixed. The cornstarch sometimes forms tiny pockets of starch if whisking isn't constant.
For the most elegant presentation, use a long serrated bread knife to slice the pie. A gentle sawing motion (never press down hard) prevents the filling from squishing out and the glaze from cracking.
This pie is best eaten within a day of assembly—after that, the cake can absorb moisture from the custard and become slightly damp. Make-ahead friendly cake and custard components, but assemble close to serving time for the best texture.

Make ahead

The cake layers can be baked up to 1 day ahead, wrapped in plastic wrap and stored at room temperature. The custard can be made up to 2 days ahead and refrigerated. Assemble the pie up to 4 hours before serving and refrigerate; the glaze will have a slightly matte finish but will still taste delicious.

Storage & reheating

Store the assembled pie, covered loosely with plastic wrap, in the refrigerator for up to 3 days. To reheat individual slices, microwave gently for 10–15 seconds or let sit at room temperature for 15 minutes to soften. Do not freeze the assembled pie, as the custard and chocolate can separate; however, unfrosted cake layers can be frozen in an airtight container for up to 3 months.

Substitutions

dark chocolate (70% cacao) → Milk or semi-sweet chocolate (55–62% cacao). Use the same amount. The glaze will be slightly sweeter and less intense. Adjust vanilla extract to taste if desired.
vanilla extract → 1 teaspoon vanilla bean paste or 0.5 teaspoon vanilla powder. Paste gives visible specks and deeper flavor; powder is more concentrated, so use less. Omit the butter if using paste to avoid greasiness.
heavy cream → Whole milk or a 1:1 blend of milk and water. The glaze will be thinner and less rich. Add 0.5 teaspoon cornstarch mixed with 1 teaspoon milk to thicken if needed.
cornstarch → 2 tablespoons (15 g) of instant flour or 2 tablespoons (20 g) of all-purpose flour plus 0.5 teaspoon xanthan gum. Both thicken equally well. Instant flour blends more smoothly; xanthan gum creates a silkier texture but can impart a slight slickness if overused.