Unapologetically delicious Boston cream cake with vanilla pastry cream topped with dark chocolate ganache is a crowd favorite for any special occasion. It’s a delicious cake worth the extra effort. Four irresistible fluffy cake layers with ultra rich thick custard. The chocolate exterior is lightly sweetened and ties it all in.
Last weekend was my (future) brother-in-law’s surprise 60th birthday party. My sister asked me to put together the cake. His party consisted of all the things he loves: weight lifting, cigars, cocktails… and Dunkin’ Donuts!
Boston cream donuts have always been my personal favorite! It’s a vanilla yeast donut with Boston cream filling (pastry cream) and has a top chocolate glaze. It inspired this cake flavor and choice of simple edible decorations: A Boston cream donut, donut holes, and powdered sugar. It’s a true American classic! Now I had to make a cake large enough to satisfy a crowd that had multiple dessert options.
Perfect cake to celebrate National Donut Day on June 2nd!
Other occasion cake recipes you may want to consider are Spooky Midnight Halloween Dark Chocolate Cake, Chocolate Cake with White Chocolate Frosting & Meringue Cookies, and Carrot Cake with Cream Cheese Frosting.
Recipe Notes Worth Mentioning Upfront
This recipe produces a fair amount of bater, after all it’s enough to feed 40-50 guests. A 6 quart mixer should handle the doubled recipe. If you have a smaller mixer, you may want to halve the recipe and do it twice. You can always taper the entire recipe down by half to make two 8″ rounds and cook roughly the same time.
Recipe makes a conservative amount of pastry cream. The layers are relatively thin (see photos below in recipe card). If you want a very pronounced thick layer of pastry cream, double the recipe. You can use the leftover egg whites to create some easy chocolate meringue cookies! We wouldn’t want you to waste eggs unnecessarily.
16oz of bittersweet chocolate is a conservative amount of chocolate for this cake. If you want a thicker layer of chocolate with less chance of chocolate cracking, increase your ratio up by 8oz more bittersweet chocolate and 1 cup more heavy whipping cream.
Ingredients
Milk: Adds moisture to the batter so it doesn’t dry.
Eggs: The egg whites make an irresistible fluffy and thick batter for a light and airy cake. The egg yolks bind the vanilla custard together. No eggs go to waste!
Vanilla Extract & Vanilla Bean: Adds warmth and delicious flavor.
Cake Flour: Has a finer texture than all purpose flour and gives a tender cake crumb This is the structure of the cake.
Sugar: Adds sweetness to the cake and pastry cream. We use granulated sugar.
Baking Powder: Gives rise to the cake.
Salt: Brings out the flavors.
Unsalted Butter: Adds necessary fats and butteriness in cake. In the pastry cream, it adds gloss and makes it fluid.
Heavy Cream: The superstar to a thick and rich pastry cream.
All Purpose Flour: Thickening agent for the pastry cream.
Bittersweet Chocolate: Not too sweet, just right. The perfect chocolate for our exterior. We sweeten it up slightly in the cooking process so it’s not too bitter.
Boston Cream Layered Cake with Chocolate Ganache
Equipment
- 2 12 " Round Cake Pan
- 2 12" Cardboard Cake Rounds
- Medium saucepan
- Parchment Paper Cut into 12" rounds
- Wire Rack
Ingredients
Cake
- 2 cups Whole Milk Room Temperature
- 12 Large Egg Whites Room Temperature
- 6 tsp Vanilla Extract
- 4 ½ cups Cake Flour Sifted
- 2 ½ cups Granulated Sugar
- 8 tsp Baking Powder
- 2 tsp Salt
- 24 tbsp Unsalted Butter Cut into 1" pieces and softened
Pastry Cream Filling
- 2 cups Heavy Cream
- 2 cups Whole Milk
- 12 Large Egg Yolks Room Temperature
- 1 cup Granulated Sugar
- ½ cup All Purpose Flour
- 8 tbsp Unsalted Butter Cut into 8 pieces, chilled
- 1 Vanilla Bean
- Optional: 4 cups half and half in lieu of heavy cream and whole milk
Dark Chocolate Ganache
- 2 cups Heavy Whipping Cream (480ml)
- 16 oz Bittersweet Chocolate (450g) Chopped
Instructions
Cake
- Adjust oven rack to middle position and heat oven to 350°F. Grease two 12-inch round cake pans, line with parchment paper, grease parchment, and flour pans.
- Whisk milk, egg whites and vanilla extract together in small bowl.
- Using stand mixer fitted with paddle, mix together the dry ingredients (cake flour, sugar, baking powder, and salt) on low speed until combined. Add butter, 1 piece at a time, and mix until only pea-size pieces remain, about 1 minute.
- Add all but ½ cup milk mixture, increase speed to medium-high, and beat until light and fluffy, about 1 minute. Reduce speed to medium-low, add remaining ½ cup milk mixture, and beat until incorporated, about 30 seconds (batter may look slightly curdled). Give batter final stir by hand. Batter should be on the thick side.
- Divide batter evenly between prepared pans and smooth tops with rubber spatula. Put both pans on the same rack. Bake cake until toothpick inserted in centers comes out clean, 23 to 25 minutes.
- Let cakes cool in pans on wire rack for 10 minutes. Carefully remove cakes from pans, discard parchment, and let cool completely, about 2 hours, before cutting.
Pastry Cream
- Heat heavy cream, whole milk, and vanilla bean in large saucepan over medium heat until just simmering.
- Meanwhile, whisk egg yolks, sugar, and salt in large bowl until smooth. Add flour to yolk mixture and whisk until incorporated.
- Remove milk mixture from heat and, whisking constantly, slowly add ½ cup to yolk mixture to temper. Whisking constantly, return tempered yolk mixture to half-and-half in saucepan.
- Return saucepan to medium heat and cook, whisking constantly, until mixture thickens slightly, about 1 minute. Reduce heat to medium-low and continue to simmer, whisking constantly, for 8 minutes.
- Increase heat to medium and cook; whisking vigorously, until bubbles burst on surface, 1 to 2 minutes. Remove saucepan from heat; whisk in butte until butter is melted and incorporated.
- Strain pastry cream through fine-mesh strainer set over medium bowl. If the butter separates, take a paper towel to blot it prior to putting parchment paper on surface… when the custard splits, it indicates the custard did not mix well in process. It's okay to blot it up and move forward.
- Press lightly greased parchment paper (or greased piece of plastic wrap) directly on surface and refrigerate until set, at least 2 hours or up to 24 hours.
Dark Chocolate Ganache
- On low heat in a medium saucepan, heat the cream until simmering. Turn off heat and add the chopped chocolate. Make sure all of the chocolate is submerged in the heated cream.
- Let stand for 3 minutes. Stir mixture until thickened and smooth.
- Take about 1 cup of the ganache into a measuring cup. Let cool in refrigerator and stir every few minutes. Be sure it doesn't get too firm. This will be sured to crumb coat the cake.Let the remaining ganache cool down until it's not not very warm, but pourable.
Assembly
- Once cakes are cooled, use a serrated knife to carefully level cakes. Then carefully cut cakes in half. You may use a toothpick method. Mark top and bottom layer with a toothpick to mark where to stack cakes.
- Whisk pastry cream briefly to make it easy to move.
- Place first cake layer on a 12" cardboard round. Take a third of the pastry cream mixture using a spatula, spread evenly across the cake. Add next layer and repeat for next 2 layers.
- Once the last layer is added to the cake. Gently press layer down and wiggle any layers to shape evenly. I usually leave a rounded piece on the top to give it some umph.
- Take the 1 cup of cooled ganache and spread an even layer to coat the cake. This will be the crumb coat. Place cake in refrigerator for 4 minutes to let the chocolate stiffen up.
- Set cake on top of a wire rack on a lipped baking sheet lined with parchment paper.
- Mix the remaining chocolate ganache in the saucepan and begin to pour in a steady stream over the center of the cake. While pouring, begin to work your way out of the cake in a spiral until you cover the edges.
- If the chocolate has stiffen too much and is not falling down the sides as expected, take a hair dryer to reheat the chocolate. Make sure you are not too close to the cake and are moving the hair dryer in fast sweeping motions all around the cake.
- If the sides have not covered enough, take a long metal icing spatula and run it along the sides of the cake to cover it fully. If there are a lot of blemishes on the cake, do a quick once over with a hair dryer. Do this sparingly. You can also choose to pour the chocolate and intend not to fully cover the sides (making it a half naked cake).
- Let the cake rest for 20-25 minutes before attempting to move.
- Run the metal icing spatula under the cake to separate it from the wire rack before attempting to move the cake. Use the icing spatula to smooth out any lumps on bottom.
- Decorate cake as desired and serve immediately. To store the cake, place in a cake box in the refrigerator. The chocolate may have some cracking if the pour was not thick enough. Serve at room temperature.
Notes
Nutrition
Nutritional information is based on third-party calculations and should be considered an estimate only. Actual nutritional content will vary based upon brands used, measuring methods, cooking method, portion sizes, and more.
