A Boston Classic Updated Via Ann Arbor: Zingerman's Boston Cream Pie

My former boss recently hosted a group of colleagues at his home for dinner and asked if I would bring dessert. Of course I would! I was having trouble deciding what to make and at the last minute I decided to try the Boston Cream Pie recipe from Zingerman's Bakehouse. The recipe headnote explains that a traditional Boston Cream Pie -- with exposed sides -- can dry out in a display case, so the Zingerman's version is completely covered in a layer of Swiss buttercream to protect it. There are five separate components in the finished cake: vanilla chiffon cake, vanilla pastry cream, vanilla Swiss buttercream, chocolate glaze, and simple syrup.

I made the pastry cream first. You steep a vanilla pod (both the pod and scraped seeds) in milk, heavy cream, sugar, and salt that have been brought to a boil. Then you add a tempered mixture of egg yolks and cornstarch and bring the mixture back to a boil for a minute. The recipe doesn't say anything about straining the pastry cream, but I put it through a sieve before whisking it for a few minutes to release excess heat and finishing it off with vanilla extract and butter. I chilled it for a few hours until it was completely cold.

To make the cake, you add the wet ingredients (egg yolks, oil, water, and vanilla) to the dry ingredients (cake flour, sugar, baking powder, and salt) and beat until smooth. Then you gradually fold in egg whites that have been beaten with sugar and cream of tartar to stiff peaks. I divided the batter between two 9-inch cake pans that were lined with parchment paper but not greased. After baking, I cooled the cakes in the pans, upside down.

For the Swiss buttercream, you heat egg whites, salt, and sugar in a double boiler and then whisk the mixture until thick, shiny, and doubled in volume. Then you gradually add softened butter and vanilla. The simple syrup is just a mixture of water, sugar, and corn syrup that has been brought to a boil, with vanilla extract added at the end.

Before assembling the cake, I leveled the cake layers. I brushed both layers with simple syrup, sandwiched them around the pastry cream, and covered the entire cake in buttercream. The pastry cream was the perfect consistency and held its shape perfectly without seeping out of the sides. While the frosted cake was in the fridge firming up, I made the chocolate glaze, which is a mixture of dark chocolate, corn syrup, and butter.

You're supposed to apply the barely warm glaze to the chilled cake, and I had some problems trying to get a smooth finish before the glaze set up. The cake pictured in the book has a lovely coating of glaze that is gracefully covering most of the sides of the cake like a satin sheet, but I ended up with clumsy drips of glaze over the sides. I did the best I could. I had to store the cake in the fridge because of the pastry cream, but I took it out and left it at room temperature for about an hour before serving. Still, the chocolate glaze was stiff and difficult to cut through. As a result, I ended up squishing and compressing the cake as I cut the slices. The pastry cream was almost exactly the same color as the cake and it was difficult to see the filling. But the cake was delicious. I love the wonderful texture of chiffon cake. It was very light but moist, and the pastry cream was fantastic. I wish the chocolate glaze could have been softer, but overall, I thought this was a terrific dessert. 

Recipe: "Boston Cream Pie" from Zingerman's Bakehouse.

Previous Posts:

• "Baked Sunday Mornings: Boston Cream Pie Cake," November 20, 2011.
• "This Lily Could Use Some Gilding: Banana Split Chiffon Cake," March 31, 2015.
• "There's More Than One Way to Skin a Nut: Hazelnut-Orange Chiffon Cake," August 23, 2013.
• "The Seedy Side of Chiffon: Pumpkin Seed Chiffon Cake," July 11, 2013.
• "Ready for the Fiesta!: Margarita Chiffon Cake," May 21, 2013.
• "Sky High Expectations: Chocolate Chiffon Cake," September 28, 2012.
• "Baked Sunday Mornings: Lady Praline Chiffon Cake," September 9, 2012.