I never ask for Boston Cream Pie at a restaurant: too many moving parts – too much room for interpretation. Think I sampled someone’s someplace (to the horror of most Europeans, Americans are happy to circle plates of dessert). The BCP missed in too many ways for me to ever order it on my own.
1. The vanilla cake should be moist. While often a traditional “sponge” cake, it can sometimes be bland and dry.
2. The vanilla custard center should be rich and smooth, but still firm enough to support a cake layer plus ganache. I’ve had gloppy and/or overly thin custard that soaks into the cake creating a wet mess.
3. Although originally conceived as chocolate fondant, the topping should be bittersweet ganache, not (Hershey’s syrup), not buttercream frosting.
I was inspired to create a gluten-free version for two reasons. First, the cover of Rebecca Reilly’s Gluten-Free Baking includes a photograph of a seductive looking Boston Cream Pie. Second, Mom loaned me Boston Firsts by Lynda Morgenroth, a book I would have otherwise passed on, but accepted because she loved it and she’s my mom. It’s about things that first occurred or were invented in Boston, including The Parker House Hotel’s Boston Cream Pie which created a sensation in 1856 when chocolate was considered a beverage and rarely used in baking.
Boston Cream Pie – Serves 8-12
1 cup (6 oz.) GF flour mix (yours, ours, or Trader Joe’s)
1 oz. almond flour (I like to make my own from toasted almonds using a coffee mill)
1/2 teaspoon baking powder
1/4 teaspoon xantham gum
1/4 teaspoon sea salt
2 large eggs, room temperature
1/2 cup (4 oz.) granulated sugar
1/2 teaspoon vanilla extract
1/2 teaspoon almond extract
1/2 cup vegetable oil
1/4 cup milk
1. Preheat the oven to 350 F and prepare an 8″ cake pan by lining it with parchment paper.
2. Measure the flour, almond flour, baking powder, xantham gum, and salt into a small mixing bowl; whisk to blend.
3. Combine the eggs and sugar in the bowl of a stand mixer and beat until light and lemon colored.
4. Combing the oil, milk, and extracts in a measuring cup; whisk to blend.
5. Add the dry and wet ingredients to the egg/sugar mixture in 4-6 alternating, ending with a portion of the dry ingredients, scraping down as needed.
6. Spread the batter into the prepared pan and bake at 350 F for 20 – 22 minutes or until the cake is firm and slightly browned at the edges. Let cool for 10-15 minutes before inverting onto a rack and cooling completely.
2/3 cup half and half
2/3 cup heavy cream
1 egg yolk
2 1/2 tablespoons cornstarch
1/3 cup (2.75 oz.) granulated sugar
pinch of salt
1 teaspoon vanilla extract
1. Combine the cornstarch with 1/3 cup of one of the creams; add the egg yolk and whisk to blend.
2. Heat the remaining cream with the sugar and salt over a medium heat until steaming. Add a little of the hot cream mixture to the egg mixture and whisk that into the rest of the hot cream, stirring constantly. Cook until thickened, about 1-3 minutes.
3. Remove from the heat, add the vanilla and pour through a fine sieve in to a bowl, stirring to push the custard through the mesh. This will remove any clumps of cornstarch or bits of egg protein. Cool a little more before covering closely with plastic wrap and chilling in the refrigerator until needed.
4 ounces heavy cream
3 1/2 ounces bittersweet chocolate, chopped
1. Heat the heavy cream in a small heavy saucepan until it just begins to boil. Remove from the heat, add the chocolate and cover for 4-5 minutes or until the chocolate melts.
2. Whisk the chocolate and cream until smooth.
TO ASSEMBLE THE BCP:
1. Slice the cooled cake in half horizontally. It can be helpful to use toothpicks as a guide.
2. Put the bottom half on a service plate and cover with the vanilla custard, spreading the custard evenly to the edge.
3. Top with the second layer and pour on the warm ganache, spreading evenly to the edge, and giving it a very gently nudge over the sides.
4. Refrigerate until an hour before serving. The ganache needs to be close to room temperature so that it’s close to the consistency of the custard.
Enjoy this Boston “first”; it won’t be the last time you make it!