Boston Cream Pie Layer Cake Squares

Despite its name, Boston cream pie is a cake, long tied to Boston’s Parker House Hotel and its custard-filled layers. These square cuts keep the classic vanilla sponge, silky pastry cream, and glossy chocolate ganache in easy shareable pieces.

Serves 6 · 40 min prep · 35 min cook

Estimate for one serving

• 455 cal
• 8g protein
• 55g carbs
• 23g fat
• 3g fiber

Every recipe here is free to read.

Ingredients

• 1 1/2 cups cake flour
• 1 cup granulated sugar
• 1/3 cup unsalted butter
• 1 1/2 cups whole milk
• 4 large eggs
• 2 tsp vanilla extract
• 1 1/2 tsp baking powder
• 1/4 tsp salt
• 3 tbsp cornstarch
• 3 egg yolks
• 1 cup semisweet chocolate chips
• 1/2 cup heavy cream
• 1 tbsp butter for greasing

Instructions

1. 1Preheat the oven to 350°F. Grease an 8-inch square pan, line the bottom with parchment, and lightly flour the sides so the thin sponge layers release cleanly.
2. 2Warm half the milk with the butter until the butter melts; keep just warm, not hot. In a large bowl whisk the eggs and sugar vigorously until thick, pale, and ribbon-like, about 4 minutes by hand or 2 with a mixer.
3. 3Sift together the cake flour, baking powder, and salt. Fold the dry ingredients into the egg foam in two additions, alternating with the warm milk-butter mixture and remaining vanilla, until the batter is smooth and pourable.
4. 4Pour the batter into the prepared pan and bake 22 to 26 minutes until the top springs back lightly and a toothpick comes out clean. Cool in the pan 10 minutes, then invert onto a rack, peel parchment, and cool completely.
5. 5Split the cooled cake horizontally into two even layers using a long serrated knife; keep the layers thin and level. Place the bottom layer back into the cleaned pan or onto a small board.
6. 6Make pastry cream by heating the remaining milk until steaming. Whisk cornstarch into the egg yolks until smooth, temper with hot milk, then cook in the saucepan over medium heat, stirring nonstop, until thick and bubbling, 3 to 5 minutes. Cool 10 minutes.
7. 7Spread the warm custard evenly over the bottom sponge layer, leaving a narrow border so it does not squeeze out. Gently set the top sponge layer in place and press very lightly to adhere.
8. 8Chill the assembled cake 45 minutes so the custard firms and the layers set. Meanwhile prepare ganache: heat cream to a bare simmer, pour over chocolate chips, rest 1 minute, then stir until glossy and slightly thickened.
9. 9Pour the ganache over the chilled cake and spread to the edges so it coats the top in an even shiny layer; allow a little to drip down the sides for classic Boston cream looks.
10. 10Refrigerate 20 more minutes until the ganache is set but still soft to the bite. Using a hot sharp knife, cut into 6 neat squares, wiping the blade between cuts for clean edges.
11. 11Plate the squares custard side visible if desired and serve slightly chilled so the sponge stays tender, the custard creamy, and the chocolate topping snappy.